Article of footwear with soil-shedding performance

ABSTRACT

The disclosure relates to articles of footwear and components thereof, including outsoles, which can be used in conditions normally conducive to the accumulation of soil on the outsoles. In particular, the disclosure relates to articles of footwear and components thereof including an outsole with an external hydrogel film having a water uptake capacity at 24 hours greater than 40% by weight. The outsoles can prevent or reduce the accumulation of soil on the footwear during wear on unpaved surfaces such as sporting fields. When the outsoles are wetted with water, the outsoles can become more compliant and/or can rapidly uptake and/or expel water, which can prevent soil from adhering to the outsole and/or can assist in shedding soil present on the outsole.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to U.S. patent application Ser.No. 14/814,191, entitled “ARTICLE OF FOOTWEAR WITH SOIL-SHEDDINGPERFORMANCE”, and filed on Jul. 30, 2015; which claims priority to U.S.Provisional Patent Application No. 62/042,719, entitled “Water-AbsorbingCompositions for Outsoles”, and filed on Aug. 27, 2014; to U.S.Provisional Patent Application No. 62/042,736, entitled “Outsoles WithAbsorptive Thermoplastic Polyurethanes”, and filed on Aug. 27, 2014; andto U.S. Provisional Patent Application No. 62/042,750, entitled“Outsoles With Absorptive Polyamides”, and filed on Aug. 27, 2014, thedisclosures of each of which are incorporated herein by reference to theextent that they do not conflict with the present disclosure.

FIELD

The present disclosure relates to articles of footwear. In particular,the present disclosure is directed to articles of footwear andcomponents thereof, including outsoles, which are used in conditionsconducive the accumulation of soil on the outsoles.

BACKGROUND

Articles of footwear of various types are frequently used for a varietyof activities including outdoor activities, military use, andcompetitive sports. The outsoles of these types of footwear often aredesigned to provide traction on soft and slippery surfaces, such asunpaved surfaces including grass and dirt. For example, exaggeratedtread patterns, lugs, cleats or spikes (both integral and removable),and rubber formulations which provide improved traction under wetconditions, have been used to improve the level of traction provided bythe outsoles.

While these conventional means generally help give footwear improvedtraction, the outsoles often accumulate soil (e.g., inorganic materialssuch as mud, dirt, sand and gravel, organic material such as grass,turf, and other vegetation, and combinations of inorganic and organicmaterials) when the footwear is used on unpaved surfaces. In someinstances, the soil can accumulate in the tread pattern (when a treadpattern is present), around and between lugs (when lugs are present), oron shafts of the cleats, in the spaces surrounding the cleats, and inthe interstitial regions between the cleats (when cleats are present).The accumulations of soil can weigh down the footwear and interfere withthe traction between the outsole and the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosure, reference should bemade to the following detailed description and accompanying drawingswherein:

FIG. 1 is a bottom isometric view of an article of footwear in anembodiment of the present disclosure having an outsole including amaterial (e.g., a film) in accordance with the present disclosure;

FIG. 2 is a bottom view of the outsole of the article of footwear shownin FIG. 1, where an upper of the footwear is omitted;

FIG. 3 is a lateral side view of the outsole shown in FIG. 2;

FIG. 4 is a medial side view of the outsole shown in FIG. 2;

FIG. 5 is an expanded sectional view of a portion of the outsole,illustrating a material in accordance with the present disclosure in adry state secured to a backing plate adjacent to a traction element(e.g., a cleat).

FIG. 5A is an expanded sectional view of the portion of the outsoleshown in FIG. 5, where the material is partially saturated and swollen.

FIG. 5B is an expanded sectional view of the portion of the outsoleshown in FIG. 5, where the material is fully saturated and swollen.

FIGS. 6-9 are expanded sectional views of the portion of the outsoleshown in FIG. 5, illustrating the soil-shedding performance of theoutsole during a foot strike motion on an unpaved surface.

FIG. 10 is a side cross-sectional view of an outsole in an aspectaccording to the disclosure including a soil-shedding material and soilbeing shed therefrom, during impact with a ground surface;

FIG. 11 is a bottom view of an article of footwear in another aspect ofthe present disclosure having an outsole including a material inaccordance with the present disclosure, the material having discrete andseparate sub-segments;

FIG. 12 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes a material inaccordance with the present disclosure, the material being present in arecessed pocket of an outsole backing plate;

FIG. 13 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes an outsolebacking plate having one or more indentations, and a material inaccordance with the present disclosure, the material being present inand over the indentations;

FIG. 14 is an expanded sectional view of a portion of an outsole inanother aspect of the present disclosure, which includes an outsolebacking plate having one or more indentations having locking members,and a material in accordance with the present disclosure, the materialbeing present in and over the indentations;

FIG. 15 is a bottom view of an article of footwear in another aspect ofthe present disclosure, which illustrates an example golf shoeapplication;

FIG. 16 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an examplebaseball shoe application;

FIG. 17 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an exampleAmerican football shoe application;

FIG. 18 is a bottom perspective view of an article of footwear inanother aspect of the present disclosure, which illustrates an examplehiking shoe application;

FIG. 19 is a photograph of an example a material of the presentdisclosure; and

FIG. 20A includes a photograph of articles of footwear with a materialaccording to the disclosure (the outside film of Example 25) after beingworn and used during wet and muddy game conditions, FIGS. 20B, 20C, 20D,20E, and 20F include photographs of articles of footwear with a materialaccording to the disclosure (the outsole film of Example 24) after beingworn and used during wet and muddy game conditions, and FIGS. 20G and20H include photographs of articles of footwear without a materialaccording to the disclosure after being worn and used during wet andmuddy game conditions.

The articles of footwear shown in the figures are illustrated for usewith a user's right foot. However, it is understood that the followingdiscussion applies correspondingly to left-footed articles of footwearas well.

DESCRIPTION

The present disclosure is directed to an article of footwear andfootwear components thereof (e.g., footwear outsoles and the like)having outsole films capable of taking up water. As used herein, theterms “article of footwear” and “footwear” are intended to be usedinterchangeably to refer to the same article. Typically, the term“article of footwear” will be used in a first instance, and the term“footwear” may be subsequently used to refer to the same article forease of readability. As used herein, the term “film” includes one ormore layers disposed on at least a portion of a surface, where thelayer(s) can be provided as a single continuous segment on the surfaceor in multiple discontinuous segments on the surface, and is notintended to be limited by any application process (e.g., co-extrusion,injection molding, lamination, spray coating, etc.).

As discussed below, it has been found these articles of footwear canprevent or reduce the accumulation of soil on the footwear during wearon unpaved surfaces. As used herein, the term “soil” can include any ofa variety of materials commonly present on a ground or playing surfaceand which might otherwise adhere to an outsole or exposed midsole of afootwear article. Soil can include inorganic materials such as mud,sand, dirt, and gravel; organic matter such as grass, turf, leaves,other vegetation, and excrement; and combinations of inorganic andorganic materials such as clay.

While not wishing to be bound by theory, it is believed that outsolefilms in accordance with the present disclosure, when sufficientlywetted with water (including water containing dissolved, dispersed orotherwise suspended materials) can provide compressive compliance and/orexpulsion of uptaken water. In particular, it is believed that thecompressive compliance of the wetted film, the expulsion of liquid fromthe wetted film, or more preferably both in combination, can disrupt theadhesion of soil at the outsole and cohesion of the soil particles toeach other.

This disruption in the adhesion and/or cohesion of soil is believed tobe a responsible mechanism for preventing (or otherwise reducing) thesoil from accumulating on the footwear outsole (due to the presence ofthe wetted outsole film). As can be appreciated, preventing soil fromaccumulating on the bottom of footwear can improve the performance oftraction elements present on the outsole during wear on unpavedsurfaces, can prevent the footwear from gaining weight due toaccumulated soil during wear, can preserve ball handling performance ofthe footwear, and thus can provide significant benefits to wearer ascompared to an article of footwear with the film present on the outsole.

In a first aspect, the present disclosure is directed to an outsole foruse in an article of footwear, where the outsole includes an outsolebacking member and a film secured to the outsole backing member anddefining an external surface of the outsole. The film compositionallyincludes a hydrogel and is capable of taking up water (e.g., has a wateruptake capacity at 24 hours greater than 40% by weight).

In some embodiments of the first aspect, the water uptake capacity ofthe film may range from 100% by weight to 900% by weight, or from 200%by weight to 500% by weight; and/or the hydrogel can comprise aphysically-crosslinked polymeric network having one or more polyurethanechains. The hydrogel can also comprise a plurality of copolymer chains,and wherein at least a portion of the copolymer chains each comprise ahard segment physically crosslinked to other hard segments of thecopolymer chains, and a soft segment covalently bonded to the hardsegment and having one or more polyether segments. The hard segment cancomprises one or more units of —C(O)NH— present in a backbone of thecopolymer chain. The film can also have a dry-state film thicknessranging from 0.1 millimeters to 1 millimeter, and a saturated-state filmthickness ranging from 0.25 millimeters to 2 millimeters.

In a second aspect, the present disclosure is directed to an article offootwear that includes an outsole substrate having a first side and asecond side, an upper operably secured to at least a portion of thefirst side of the outsole substrate, and a ground-facing film operablysecured to at least a portion of the second side of the outsolesubstrate. The ground-facing film comprises a hydrogel and is capable oftaking up water (e.g., has a water uptake capacity at 24 hours rangingfrom 40% by weight to 900% by weight).

In some embodiments of the second aspect, the outsole substratecomprises a thermoplastic polyurethane, and wherein the hydrogel of theground-facing film comprises a thermoplastic polyurethane hydrogel. Inother aspects, the outsole substrate comprises a thermoplasticpolyamide, and wherein the hydrogel of the ground-facing film comprisesa thermoplastic polyamide hydrogel. The water uptake capacity of theground-facing film may also ranges from 200% by weight to 500% byweight.

In some further embodiments, the article of footwear further comprisesone or more traction elements operably secured to the outsole substrate,where each of the traction elements comprises a terminal edge, and wherethe film does not cover the terminal edges of any of the one or moretraction elements. Moreover, the hydrogel can comprise a plurality ofcopolymer chains, and wherein at least a portion of the copolymer chainseach comprise a hard segment physically crosslinked to other hardsegments of the copolymer chains, and a hydrophilic soft segmentcovalently bonded to the hard segment with an ester linkage.

A third aspect of the present disclosure is directed to a method ofmanufacturing an article of footwear, which includes providing anoutsole, the outsole having an outsole backing member and a film securedto the outsole backing member, where the film comprises a hydrogel andis capable of taking up water (e.g., has a water uptake capacity at 24hours greater than 40% by weight). The method also includes securing theoutsole to an upper such that the film defines a ground-facing surfaceof the article of footwear.

In some embodiments of the third aspect, the water uptake capacity ofthe film ranges from 200% by weight to 500% by weight, and/or theoutsole backing member compositionally comprises a thermoplasticpolyurethane, where the hydrogel comprises a crosslinked polymericnetwork having copolymer chains that are physically crosslinked. Inother aspects, the copolymer chains are substantially free of aromaticgroups, and/or the film has a dry-state film thickness ranging from 0.1millimeters to 1 millimeter. Furthermore, the method can also includesecuring one or more traction elements to the outsole.

As used herein, the term “weight” refers to a mass value, such as havingthe units of grams, kilograms, and the like. Further, the recitations ofnumerical ranges by endpoints include the endpoints and all numberswithin that numerical range. For example, a concentration ranging from40% by weight to 60% by weight includes concentrations of 40% by weight,60% by weight, and all water uptake capacities between 40% by weight and60% by weight (e.g., 40.1%, 41%, 45%, 50%, 52.5%, 55%, 59%, etc. . . .).

As used herein, the term “providing”, such as for “providing anoutsole”, when recited in the claims, is not intended to require anyparticular delivery or receipt of the provided item. Rather, the term“providing” is merely used to recite items that will be referred to insubsequent elements of the claim(s), for purposes of clarity and ease ofreadability.

As used herein, the terms “preferred” and “preferably” refer toembodiments of the invention that may afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the present disclosure.

As used herein, the terms “about” and “substantially” are used hereinwith respect to measurable values and ranges due to expected variationsknown to those skilled in the art (e.g., limitations and variability inmeasurements).

The article of footwear of the present disclosure may be designed for avariety of uses, such as sporting, athletic, military, work-related,recreational, or casual use. Primarily, the article of footwear isintended for outdoor use on unpaved surfaces (in part or in whole), suchas on a ground surface including one or more of grass, turf, gravel,sand, dirt, clay, mud, and the like, whether as an athletic performancesurface or as a general outdoor surface. However, the article offootwear may also be desirable for indoor applications, such as indoorsports including dirt playing surfaces for example (e.g., indoorbaseball fields with dirt infields). As used herein, the terms “at leastone” and “one or more of” an element are used interchangeably, and havethe same meaning that includes a single element and a plurality of theelements, and may also be represented by the suffix “(s)” at the end ofthe element. For example, “at least one polyurethane”, “one or morepolyurethanes”, and “polyurethane(s)” may be used interchangeably andhave the same meaning.

In preferred embodiments, the article of footwear is designed use inoutdoor sporting activities, such as global football/soccer, golf,American football, rugby, baseball, running, track and field, cycling(e.g., road cycling and mountain biking), and the like. The article offootwear can optionally include traction elements (e.g., lugs, cleats,studs, and spikes) to provide traction on soft and slippery surfaces.Cleats, studs and spikes are commonly included in footwear designed foruse in sports such as global football/soccer, golf, American football,rugby, baseball, and the like, which are frequently played on unpavedsurfaces. Lugs and/or exaggerated tread patterns are commonly includedin footwear including boots design for use under rugged outdoorconditions, such as trail running, hiking, and military use.

FIGS. 1-4 illustrate an example article of footwear of the presentdisclosure, referred to as an article of footwear 100, and which isdepicted as footwear for use in global football/soccer applications. Asshown in FIG. 1, the footwear 100 includes an upper 110 and an outsole112 as footwear article components, where outsole 112 includes aplurality of traction elements 114 (e.g., cleats) and an outsole film116 at its external or ground-facing side or surface. While many of theembodied footwear of the present disclosure preferably include tractionelements such as cleats, it is to be understood that in otherembodiments, the incorporation of cleats is optional.

The upper 110 of the footwear 100 has a body 118 which may be fabricatedfrom materials known in the art for making articles of footwear, and isconfigured to receive a user's foot. For example, the upper body 118 maybe made from or include one or more components made from one or more ofnatural leather; a knit, braided, woven, or non-woven textile made inwhole or in part of a natural fiber; a knit, braided, woven or non-woventextile made in whole or in part of a synthetic polymer, a film of asynthetic polymer, etc.; and combinations thereof. The upper 110 andcomponents of the upper 110 may be manufactured according toconventional techniques (e.g., molding, extrusion, thermoforming,stitching, knitting, etc.). While illustrated in FIG. 1 with a genericdesign, the upper 110 may alternatively have any desired aestheticdesign, functional design, brand designators, and the like.

The outsole 112 may be directly or otherwise operably secured to theupper 110 using any suitable mechanism or method. As used herein, theterms “operably secured to”, such as for an outsole that is operablysecured to an upper, refers collectively to direct connections, indirectconnections, integral formations, and combinations thereof. Forinstance, for an outsole that is operably secured to an upper, theoutsole can be directly connected to the upper (e.g., with an adhesive),the outsole can be indirectly connected to the upper (e.g., with anintermediate midsole), can be integrally formed with the upper (e.g., asa unitary component), and combinations thereof.

For example, the upper 110 may be stitched to the outsole 112, or theupper 110 may be glued to the outsole 112, such as at or near a biteline 120 of the upper 110. The footwear 100 can further include amidsole (not shown) secured between the upper 110 and the outsole 112,or can be enclosed by the outsole 112. When a midsole is present, theupper 110 may be stitched, glued, or otherwise attached to the midsoleat any suitable location, such as at or below the bite line 120.

As further shown in FIGS. 1 and 2, the layout of outsole 112 can besegregated into a forefoot region 122, a midfoot region 124, and a heelregion 126. The forefoot region 122 is disposed proximate a wearer'sforefoot, the midfoot region 124 is disposed between the forefoot region122 and the heel region 126, and the heel region 126 is disposedproximate a wearer's heel and opposite the forefoot region 122. Theoutsole 112 may also include a forward edge 128 at the forefoot region122 and a rearward edge 130 at the heel region 126. In addition to theselongitudinal designations, the left/right sides of outsole 112 can alsobe respectively designated by a medial side 132 and a lateral side 134.

Each of these designations can also apply to the upper 110 and moregenerally to the footwear 100, and are not intended to particularlydefine structures or boundaries of the footwear 100, the upper 110, orthe outsole 112. As used herein, directional orientations for anarticle, such as “upward”, “downward”, “top”, “bottom”, “left”, “right”,and the like, are used for ease of discussion, and are not intended tolimit the use of the article to any particular orientation.Additionally, references to “ground-facing surface”, “ground-facingside”, and the like refer to the surface or side of footwear that facethe ground during normal use by a wearer as standing. These terms arealso used for ease of discussion, and are not intended to limit the useof the article to any particular orientation.

The outsole 112 also includes a backing plate or 136, which, in theshown example, extends across the forefoot region 122, the midfootregion 124, and the heel region 126. The backing plate 136 is an examplebacking member or other outsole substrate for use in an article offootwear, and can provide structural integrity to the outsole 112.However, the backing plate 136 can also be flexible enough, at least inparticular locations, to conform to the flexion of a wearer's footduring the dynamic motions produced during wear. For example, as shownin FIGS. 1 and 2, the backing plate 136 may include a flex region 138 atthe forefoot region 122, which can facilitate flexion of the wearer'stoes relative to the foot in active use of the footwear 100.

The backing plate 136 may have a top (or first) surface (or side) 142(best shown in FIGS. 3 and 4), a bottom (or second) surface (or side)144, and a sidewall 146, where the sidewall 146 can extend around theperimeter of the backing plate 136 at the forward edge 128, the rearwardedge 130, the medial side 132, and the lateral side 134. The top surface142 is the region of the backing plate 136 (and the outsole 112 moregenerally) that may be in contact with and operably secured to the upper110 and/or to any present midsole or insole.

The bottom surface 144 is a ground-facing surface of the backing plate136 that is covered (or at least partially covered) by the film 116secured thereto, and would otherwise be configured to contact a groundsurface, whether indoors or outdoors, if the film 116 were otherwiseomitted. The bottom surface 144 is also the portion of outsole 112 thatthe traction elements 114 can extend from, as discussed below.

The backing plate 136 can be manufactured with one or more layers, maybe produced from any suitable material(s), and can provide a goodinterfacial bond to the film 116, as discussed below. Examples ofsuitable materials for the backing plate 136 include one or morepolymeric materials such as thermoplastic elastomers; thermosetpolymers; elastomeric polymers; silicone polymers; natural and syntheticrubbers; composite materials including polymers reinforced with carbonfiber and/or glass; natural leather; metals such as aluminum, steel andthe like; and combinations thereof.

In particular embodiments, the backing plate 136 is manufactured fromone or more polymeric materials having similar chemistries to that ofthe film 116. In other words, the backing plate and the film can bothcomprise or consist essentially of polymers having the same or similarfunctional groups, and/or can comprise or consist essentially ofpolymers having the same or similar levels of polarity. For example, thebacking plate and the film can both comprise or consist essentially ofone or more polyurethanes (e.g., thermoplastic polyurethanes), one ormore polyamides (e.g., thermoplastic polyamides), one or more polyethers(e.g., thermoplastic polyethers), one or more polyesters (e.g.,thermoplastic polyesters), or the like. The similar chemistries can bebeneficial for improving manufacturing compatibilities between thematerials of the film 116 and the backing plate 136, and also forimproving their interfacial bond strength. Alternatively, one or moretie layers (not shown) can be applied between the backing plate 136 andthe film 116 in order to improve their interlayer bonding.

As used herein, the term “polymer” refers to a molecule havingpolymerized units of one or more species of monomer. The term “polymer”is understood to include both homopolymers and copolymers. The term“copolymer” refers to a polymer having polymerized units of two or morespecies of monomers, and is understood to include terpolymers. As usedherein, reference to “a” polymer or other chemical compound refers oneor more molecules of the polymer or chemical compound, rather than beinglimited to a single molecule of the polymer or chemical compound.Furthermore, the one or more molecules may or may not be identical, solong as they fall under the category of the chemical compound. Thus, forexample, “a” polylaurolactam is interpreted to include one or morepolymer molecules of the polylaurolactam, where the polymer moleculesmay or may not be identical (e.g., different molecular weights and/orisomers).

The traction elements 114 may each include any suitable cleat, stud,spike, or similar element configured to enhance traction for a wearerduring cutting, turning, stopping, accelerating, and backward movement.The traction elements 114 can be arranged in any suitable pattern alongthe bottom surface 144 of the backing plate 136. For instance, thetraction elements 114 can be distributed in groups or clusters along theoutsole 112 (e.g., clusters of 2-8 traction elements 114). As best shownin FIGS. 1 and 2, the traction elements 114 can be grouped into acluster 147A at the forefoot region 122, a cluster 147B at the midfootregion 124, and a cluster 147C at the heel region 126. In this example,six of the traction elements 114 are substantially aligned along themedial side 132 of the outsole 112, and the other six traction elements114 are substantially aligned along the lateral side 134 of the outsole112.

The traction elements 114 may alternatively be arranged along theoutsole 112 symmetrically or non-symmetrically between the medial side132 and the lateral side 134, as desired. Moreover, one or more of thetraction elements 114 may be arranged along a centerline of outsole 112between the medial side 132 and the lateral side 134, such as a blade114A, as desired to enhance or otherwise modify performance.

Alternatively (or additionally), traction elements can also include oneor more front-edge traction elements 114, such as one or more blades114B, one or more fins 114C, and/or one or more cleats (not shown)operably secured to (e.g., integrally formed with) the backing plate 136at a front-edge region between forefoot region 122 and cluster 147A. Inthis application, the film 116 can optionally extend across the bottomsurface 144 at this front-edge region while maintaining good tractionperformance.

Furthermore, the traction elements 114 may each independently have anysuitable dimension (e.g., shape and size). For instance, in somedesigns, each traction element 114 within a given cluster (e.g.,clusters 147A, 147B, and 147C) may have the same or substantially thesame dimensions, and/or each traction element 114 across the entirety ofthe outsole 112 may have the same or substantially the same dimensions.Alternatively, the traction elements 114 within each cluster may havedifferent dimensions, and/or each traction element 114 across theentirety of the outsole 112 may have different dimensions.

Examples of suitable shapes for the traction elements 114 includerectangular, hexagonal, cylindrical, conical, circular, square,triangular, trapezoidal, diamond, ovoid, as well as other regular orirregular shapes (e.g., curved lines, C-shapes, etc. . . . ). Thetraction elements 114 may also have the same or different heights,widths, and/or thicknesses as each other, as further discussed below.Further examples of suitable dimensions for the traction elements 114and their arrangements along the backing plate 136 include thoseprovided in soccer/global football footwear commercially available underthe tradenames “TIEMPO”, “HYPERVENOM”, “MAGISTA”, and “MERCURIAL” fromNike, Inc. of Beaverton, Oreg.

The traction elements 114 may be incorporated into the backing plate 136by any suitable mechanism such that the traction elements 114 preferablyextend from the bottom surface 144. For example, as discussed below, thetraction elements 114 may be integrally formed with the backing plate136 through a molding process (e.g., for firm ground (FG) footwear).Alternatively, the backing plate 136 may be configured to receiveremovable traction elements 114, such as screw-in or snap-in tractionelements 114. In these embodiments, the backing plate 136 may includereceiving holes (e.g., threaded or snap-fit holes, not shown), and thetraction elements 114 can be screwed or snapped into the receiving holesto secure the traction elements 114 to the backing plate 136 (e.g., forsoft ground (SG) footwear).

In further examples, a first portion of the traction elements 114 can beintegrally formed with the backing plate 136 and a second portion of thetraction elements 114 can be secured with screw-in, snap-in, or othersimilar mechanisms (e.g., for SG pro footwear). The traction elements114 may also be configured as short studs for use with artificial ground(AG) footwear, if desired. In some applications, the receiving holes maybe raised or otherwise protrude from the general plane of the bottomsurface 144 of the backing plate 136. Alternatively, the receiving holesmay be flush with the bottom surface 144.

The traction elements 114 can be fabricated from any suitable materialfor use with the outsole 112. For example, the traction elements 114 mayinclude one or more of polymeric materials such as thermoplasticelastomers; thermoset polymers; elastomeric polymers; silicone polymers;natural and synthetic rubbers; composite materials including polymersreinforced with carbon fiber and/or glass; natural leather; metals suchas aluminum, steel and the like; and combinations thereof. Inembodiments in which the traction elements 114 are integrally formedwith the backing plate 112 (e.g., molded together), the tractionelements 114 preferably include the same materials as the backing plate112 (e.g., thermoplastic materials). Alternatively, in embodiments inwhich the traction elements 114 are separate and insertable intoreceiving holes of the backing plate 112, the traction elements 114 caninclude any suitable materials that can secured in the receiving holesof the backing plate 112 (e.g., metals and thermoplastic materials).

The backing plate 136 (and more generally, the outsole 112) may alsoinclude other features other than the traction elements 114 that canprovide support or flexibility to the outsole and/or for aestheticdesign purposes. For instance, the backing plate 136 may also includeridges 148 that may be raised or otherwise protrude from the generalplane of the bottom surface 144.

As shown, ridges 148 can extend along the arrangement pathways of thetraction elements 114, if desired. These features (e.g., ridges 148) canbe integrally formed into the backing plate 136, or alternatively, beremovable features that are securable to the backing plate 136. Suitablematerials for these features include those discussed above for thetraction elements 114.

The backing plate 136 (and more generally, the outsole 112) may alsoinclude other features such as exaggerated tread patterns, lugs, and thelike, which are configured to contact the ground or playing surface toincrease traction, to enhance performance, or for aesthetic designpurposes. These other features can be present on the outsole in place ofor in addition to the traction elements 114, and can be formed from thesuitable materials discussed above for the traction elements 114.

As further shown in FIGS. 3 and 4, the traction elements 114 can bearranged such that when footwear 100 rests on a flat surface 149, thebottom surface 144 of backing plate 136 and the film 116 are offset fromthe flat surface 149. This offset is present even when the film 116 isfully saturated and swollen, as discussed below. As such, the tractionelements 114 can receive the greatest levels of shear and abrasivecontact with surfaces during use, such as by digging into soil duringcutting, turning, stopping, accelerating, backward movements, and thelike. In comparison, the film 116 at its offset location can remainpartially protected from a significant portion of these shear andabrasive conditions, thereby preserving its integrity during use.

FIG. 5 is an expanded sectional view of the film 116 and the bottomsurface 144 of the backing plate 136 at one of the traction elements114. In this shown example, the traction element 114, which can berepresentative of one or more of the other traction elements 114, isintegrally molded with the backing plate 136 and includes a shaft 150that protrudes downward beyond the bottom surface 144 and the film 116.The shaft 150 itself may include an outer side surface 152 and aterminal edge 154. The terminal edge 154 of the shaft 150 is the distalend of the traction element 114, opposite from the bottom surface 144,and is the portion of the traction element 114 that can initiallycontact and penetrate into a playing or ground surface.

As mentioned above, the traction element 114 may have any suitabledimensions and shape, where the shaft 150 (and the outer side surface152) can correspondingly have rectangular, hexagonal, cylindrical,conical, circular, square, triangular, trapezoidal, diamond, ovoid, aswell as other regular or irregular shapes (e.g., curved lines, C-shapes,etc. . . . ). Similarly, the terminal edge 154 can have dimensions andsizes that correspond to those of the outer side surface 152, and can besubstantially flat, sloped, rounded, and the like. Furthermore, in someembodiments, the terminal edge 154 can be substantially parallel to thebottom surface 144 and/or the film 116.

Examples of suitable average lengths 156 for each shaft 150 relative tobottom surface 144 range from 1 millimeter to 20 millimeters, from 3millimeters to 15 millimeters, or from 5 millimeters to 10 millimeters,where, as mentioned above, each traction element 114 can have differentdimensions and sizes (i.e., the shafts 150 of the various tractionelements 114 can have different lengths).

In the example shown in FIGS. 1-5, the film 116 is present on the entirebottom surface 144 of the backing plate 136 between (and not including)the traction elements 114. For instance, as shown in FIG. 5, the film116 can cover the bottom surface 144 at locations around the shaft 150of each traction element 114, such that film 116 does not cover theouter side surface 152 or the terminal edge 154 of the traction element114, other than optionally at a base region 158 of the shaft 150. Thiscan preserve the integrity of the film 116 and preserve tractionperformance of the traction elements 114. In some embodiments, the film116 does not cover or contact any portion of the outer side surface 152of the shaft 150. In other embodiments, the base region 158 that thefilm 116 (in a dry state) covers and contacts the outer side surface 152is less than 25%, less than 15%, or less than 10% of the length of theshaft 150, as an average distance measured from the bottom surface 144at the traction element 114.

As can be seen in FIG. 5, the film 116 is preferably a thin film tominimize or otherwise reduce its impact on the traction elements 114.Examples of suitable average thicknesses for the film 116 in a dry state(referred to as a dry-state film thickness 160) range from 0.025millimeters to 5 millimeters, from 0.5 millimeters to 3 millimeters,from 0.25 millimeters to 1 millimeter, from 0.25 millimeters to 2millimeters, from 0.25 millimeters to 5 millimeters, from 0.15millimeters to 1 millimeter, from 0.15 millimeters to 1.5 millimeters,from 0.1 millimeters to 1.5 millimeters, from 0.1 millimeters to 2millimeters, from 0.1 millimeters to 5 millimeters, from 0.1 millimetersto 1 millimeter, or from 0.1 millimeters to 0.5 millimeters. Asdepicted, the thicknesses for the film 116 are measured between theinterfacial bond at the bottom surface 144 of the backing plate 136 andan exterior surface of the film 116 (referred to as a film surface 162).

In some alternative embodiments, the film 116 can also (oralternatively) be present on one or more regions of the tractionelements 114. These embodiments can be beneficial, for example, inapplications where the traction element 114 has a central base withmultiple shafts 150 that protrude from the periphery of the centralbase. In such embodiments, the film 116 can be present on at least thecentral base of the traction element 114. Furthermore, for someapplications, the film 116 may also cover the entirety of one or more ofthe traction elements 114 (e.g., on the shaft 150).

Presence of the film 116 on the ground-facing side of outsole 112 (i.e.,on bottom surface 144) allows the film 116 to come into contact withsoil, including wetted soil during use, which is believed to enhance thesoil-shedding performance for the footwear 100, as explained below.However, the film 116 can also optionally be present on one or morelocations of the sidewall 146 of the backing plate 136.

As briefly mentioned above, the film 116 can compositionally include amaterial that allows the film 116 to absorb or otherwise take up water.For example, the material can include a crosslinked polymeric networkthat can quickly take up water from an external environment (e.g., frommud, wet grass, presoaking, and the like).

Moreover, it is believed that this uptake of water by the film 116causes the polymer network of the material to untwist and stretch underthe pressure of the received water, while retaining its overallstructural integrity through its crosslinking (physical or covalentcrosslinking). This stretching and expansion of the polymer network cancause the film 116 to swell and become more compliant (e.g.,compressible, expandable, and stretchable). As used herein, the term“compliant” refers to the stiffness of an elastic material, and can bedetermined by the storage modulus of the material. The lower the degreeof crosslinking in a material, or the greater the distance betweencrosslinks in a material, the more compliant the material.

The swelling of the film 116 can be observed as an increase in filmthickness from the dry-state thickness 160 of the film 116 (shown inFIG. 5), through a range of intermediate-state thicknesses (e.g.,thickness 163, shown in FIG. 5A) as additional water is absorbed, andfinally to a saturated-state thickness 164 (shown in FIG. 5B), which isan average thickness of the film 116 when fully saturated with water.For example, the saturated-state thickness 164 for the fully saturatedfilm 114 can be greater than 150%, greater than 200%, greater than 250%,greater than 300%, greater than 350%, greater than 400%, or greater than500%, of the dry-state thickness 160 for the same film 116.

In some embodiments, the saturated-state thickness 164 for the fullysaturated film 114 range from 150% to 500%, from 150% to 400%, from 150%to 300%, or from 200% to 300% of the dry-state thickness 160 for thesame film 116. Examples of suitable average thicknesses for the film 116in a wet state (referred to as a saturated-state thickness 164) rangefrom 0.2 millimeters to 10 millimeters, from 0.2 millimeters to 5millimeters, from 0.2 millimeters to 2 millimeters, from 0.25millimeters to 2 millimeters, or from 0.5 millimeters to 1 millimeter.

Preferably, the film 116 material can quickly take up water that is incontact with the film 116. For instance, the film 116 can take up waterfrom mud and wet grass, such as during a warmup period prior to acompetitive match. Alternatively (or additionally), the film 116 can bepre-conditioned with water so that the film 116 is partially or fullysaturated, such as by spraying or soaking the outsole 112 with waterprior to use.

The total amount of water that the film 116 can take up depends on avariety of factors, such as its composition (e.g., its hydrophilicity),its cross-linking density, its thickness, and its interfacial bond tothe backing plate 136. For example, it is believed that a film materialhaving a higher hydrophilicity and a lower cross-linking density canincrease the maximum water uptake for the film 116. On the other hand,the interfacial bond between the film 116 and the bottom surface 144 ofthe backing plate 136 can potentially restrict the swelling of the film116 due to its relatively thin dimensions. Accordingly, as describedbelow, the maximum water uptake and the maximum percent swell of thefilm 116 can differ between the film 116 in a neat state (isolated filmby itself) and the film 116 as present on the backing plate 136.

The water uptake capacity and the water uptake rate of the film 116 aredependent on the size and shape of its geometry, and are typically basedon the same factors. However, it has been found that, to account forpart dimensions when measuring water uptake capacity, it is possible toderive an intrinsic, steady-state material property. Therefore,conservation of mass can be used to define the ratio of water weightabsorbed to the initial dry weight of the film 116 at very long timescales (i.e. when the ratio is no longer changing at a measurable rate.)

Conversely, the water uptake rate is transient and is preferably definedkinetically. The three primary factors for water uptake rate for a givenpart geometry include time, thickness, and the exposed surface areaavailable for water flux. Once again, the weight of water taken up canbe used as a metric of water uptake rate, but the water flux can also beaccounted for by normalizing by the exposed surface area. For example, athin rectangular film can be defined by 2×L×W, where L is the length ofone side and W is the width. The value is doubled to account for the twomajor surfaces of the film, but the prefactor can be eliminated when thefilm has a non-absorbing, structural layer secured to one of the majorsurfaces (e.g., with an outsole backing plate).

Normalizing for thickness and time can require a more detailed analysisbecause they are coupled variables. Water penetrates deeper into thefilm as more time passes in the experiment, and therefore, there is morefunctional (e.g., absorbent) material available at longer time scales.One dimensional diffusion models can explain the relationship betweentime and thickness through material properties, such as diffusivity. Inparticular, the weight of water taken up per exposed surface area shouldyield a straight line when plotted against the square root of time.

However, several factors can occur where this model does not representthe data well. First, at long times absorbent materials become saturatedand diffusion kinetics change due to the decrease in concentrationgradient of the water. Second, as time progresses the material can beplasticized to increase the rate of diffusion, so once again the modeldo longer represents the physical process. Finally, competing processescan dominate the water uptake or weight change phenomenon, typicallythrough surface phenomenon such as physisorption on a rough surface dueto capillary forces. This is not a diffusion driven process, and thewater is not actually be taken up into the film.

Even though the film 116 can swell as it takes up water and transitionsbetween the different film states with corresponding thicknesses 160,163, and 164, the saturated-state thickness 164 of the film 116preferably remains less than the length 156 of the traction element 114.This selection of the film 116 and its corresponding dry and saturatedthicknesses ensures that the traction elements 114 can continue toprovide ground-engaging traction during use of the footwear 100, evenwhen the film 116 is in a fully swollen state. For example, the averageclearance difference between the lengths 156 of the traction elements114 and the saturated-state thickness 164 of the film 116 is desirablyat least 8 millimeters. For example, the average clearance distance canbe at least 9 millimeters, 10 millimeters, or more.

As also mentioned above, in addition to swelling, the compliance of thefilm 116 may also increase from being relatively stiff (dry state) tobeing increasingly stretchable, compressible, and malleable (inpartially and fully saturated states). The increased complianceaccordingly can allow the film 116 to readily compress under an appliedpressure (e.g., during a foot strike on the ground), which can quicklyexpel at least a portion of its retained water (depending on the extentof compression). While not wishing to be bound by theory, it is believedthat this combination of compressive compliance and water expulsion candisrupt the adhesion and cohesion of soil at outsole 112, which preventsor otherwise reduces the accumulation of soil on outsole 112.

In addition to quickly expelling water, the compressed film 116 may alsobe capable of quickly re-absorbing water when the compression isreleased (e.g., liftoff from a foot strike during normal use). As such,during use in a wet or damp environment (e.g., a muddy or wet ground),the film 116 can dynamically expel and re-uptake water over successivefoot strikes. As such, the film 116 can continue to prevent soilaccumulation over extended periods of time (e.g., during an entirecompetitive match), particularly when there is ground water availablefor re-uptake.

FIGS. 6-9 illustrate an example method of using footwear 100 with amuddy or wet ground 166, which depict the believed mechanism forpreventing soil accumulation on the outsole 112. It is known that thesoil of the ground 166 can accumulate on an outsole (e.g., between thetraction elements) during normal athletic or casual use, in particularwhen the ground 166 is wet. The soil is believed to accumulate on theoutsole due to a combination of adhesion of the soil particles to thesurface of the outsole and cohesion of the soil particles to each other.In order to break these adhesive/cohesive forces, the soil particlesneed to be subjected to stresses high enough to exceed theiradhesive/cohesive activation energies. When this is achieved, the soilparticles can then move or flow under the applied stresses, whichdislodge or otherwise shed portions of the soil from the outsole.

However, during typical use of cleated footwear, such as duringcompetitive sporting events (e.g., global football/soccer matches,golfing events, and American football games), the actions of walking andrunning are not always sufficient to dislodge the soil from the outsole.This can result in the soil sticking to the outsoles, particularly inthe interstitial regions where compaction forces in the normal directionare maximized between the individual traction elements. As can beappreciated, this soil can quickly accumulate to increase the weight ofthe footwear and reduce the effectiveness of the traction elements(e.g., because they have less axial or normal extent capable of engagingwith the ground 166), each of which can have a significant impact onathletic performance.

The incorporation of the film 116 to the outsole 112, however, isbelieved to disrupt the adhesion and cohesion of soil at the outsole112, thereby reducing the adhesive/cohesive activation energiesotherwise required to induce the flow of the soil particles. As shown inFIG. 6, the footwear 100 can be provided in a pre-conditioned statewhere the film 116 is partially or fully saturated with water. This canbe accomplished in a variety of manners, such as spraying the outsole112 with water, soaking the outsole 112 in water, or otherwise exposingthe film 116 to water in a sufficient amount for a sufficient duration.Alternatively (or additionally), when water or wet materials are presenton the ground 166, footwear 100 can be used in a conventional manner onthe ground 166 until the film 116 absorbs a sufficient amount of waterfrom the ground 166 or wet materials to reach its pre-conditioned state.

During a foot strike, the downward motion of the footwear 100(illustrated by arrow 168) causes the traction element 114 to contactthe ground 166. As shown in FIG. 7, the continued applied pressure ofthe foot strike can cause the traction element 114 to penetrate into thesofter soil of the ground 166 until the film surface 162 of the film 116contacts the ground 166. As shown in FIG. 8, further applied pressure ofthe foot strike can press the film 116 into the ground 166, thereby atleast partially compressing the film 116 under the applied pressure(illustrated by arrows 170).

As can be seen, this compression of the film 116 into the soil of theground 166 typically compacts the soil, increasing the potential for thesoil particles to adhere to outsole 112 and to cohesively adhere to eachother (clumping together). However, the compression of the film 116 mayalso expel at least a portion of its uptaken water into the soil of theground 166 (illustrated by arrows 172). It is believed that as the wateris expelled through the film surface 162 of the film 116, the pressureof the expelled water can disrupt the adhesion of the soil to the filmsurface 162 at this interface.

Additionally, once expelled into the soil, it is also believed that thewater may also modify the rheology of the soil adjacent to the filmsurface 162 (e.g., watering down the soil to a relatively muddier orwetter state). This is believed to essentially spread out the soilparticles in the water carrier and weaken their cohesive forces (e.g.,mechanical/ionic/hydrogen bonds). Each of these mechanisms from theexpelled water is believed to lower the required stresses need todisrupt the adhesion of the soil from the outsole 112. As such, thestresses typically applied during athletic performances (e.g., whilerunning, handling the ball with the footwear, and kicking the ball) canexceed the cohesive/adhesive activation energies more frequently.

As shown in FIG. 9, when the footwear 100 is lifted following the footstrike (illustrated by arrow 174), it is believed that the compressionapplied to the film 116 is released, and so the film 116 can be free toexpand. In some examples, it has been found that, when the outsole 112is lifted apart from the ground 166, a thin water layer can remain incontact with the film surface 162, which can quickly re-uptake into thefilm 116. This quick re-uptake of water from the film surface 162 aftercompression is removed (e.g., within about 1, 2, or 5 seconds) canquickly swell the film 116 back at least partially to itspreviously-swelled state (depending on the amount of water re-absorbed),as illustrated by arrows 176.

This cyclic compression and expansion from repeated, rapid, and/orforceful foot strikes during use of the footwear 100 can alsomechanically disrupt the adhesion of any soil still adhered to the filmsurface 162, despite the relatively small thickness of the film 116 inany of its various states of water saturation (e.g., partially to fullysaturated). In particular, the increased compliance is believed, undersome conditions, to lead to inhomogeneous shear states in the soil whencompressed in the normal or vertical direction, which can also lead toincreased interfacial shear stresses and a decrease in soilaccumulation.

In some embodiments, the film 116 can swell during water re-uptake (andalso during initial uptake) in a non-uniform manner. In suchembodiments, the uptaken water may tend to travel in a pathperpendicular to the film surface 162, and so may not migratesubstantially in a transverse direction generally in the plane of thefilm 116 once absorbed. This uneven, perpendicular water uptake andrelative lack of transverse water intra-film transport can form anirregular or rough texture or small ridges for the film surface 162. Thepresence of these small ridges on the irregular film surface 162 fromthe non-uniform swelling are also believed to potentially furtherdisrupt the adhesion of the soil at the film surface 162, and thus mayloosen the soil and further promote soil shedding. The uneven, ridgedfilm surface 162 can also be seen in the photograph of FIG. 19 of anexemplary water-saturated film 116 according to the present disclosure.

In addition to the uptake, compression, expulsion, re-uptake, andswelling cycle discussed above, the increased compliance of the film116, for example elongational compliance in the longitudinal direction,may allow the film 116 to be more malleable and stretchable whenswelled. For example, as illustrated in FIG. 10, during a foot rotationin a foot strike (e.g., as the foot generally rolls from heel to toeduring a stride), the outsole 112 and the film 116 are correspondinglyflexed (e.g., inducing compression forces illustrated by arrows 170).

The increased elongation or stretchiness of the film 116 when partiallyor fully saturated with water can increase the extent that the film 116stretches during this flexing, which can induce additional shear on anysoil adhered to the film surface 162. As illustrated, a rolling groundstrike creates a curved outsole 112 and a curved compressed film 116,which can cause water to be expelled therefrom and transverse filmstretching forces being induced to pull apart and shed the soil. Thecompression forces (illustrated by arrows 170) on the film 116, whichcan help to expel the water can be particularly strong at points ofcontact with the ground 166 and/or where the radius of curvature of thecurved outsole 112/curved film 116 is relatively small or at itsminimum.

The foregoing properties of the film 116 related tocompression/expansion compliance and the elongation compliance arebelieved to be closely interrelated, and they can depend on the samefilm 116 properties (e.g., a hydrophilic film able to able to rapidlytake up and expel relatively large amounts of water compared to the filmsize or thickness). A distinction is in their mechanisms for preventingsoil accumulation, for example surface adhesion disruption versus shearinducement. The water re-uptake is believed to potentially act toquickly expand or swell the film 116 after being compressed to expelwater. Rapid water uptake can provide a mechanism for replenishing thefilm 116 water content between foot strikes. Rapid replenishment of thefilm 116 water content can restore the film 116 to its compliant state,returning it to a state where stretching and shearing forces cancontribute to debris shedding. In addition, replenishment of the film116 water content can permit subsequent water expulsion to provide anadditional mechanism for preventing soil accumulation (e.g., applicationof water pressure and modification of soil rheology). As such, the waterabsorption/expulsion cycle can provide a unique combination forpreventing soil accumulation on the outsole 112 of the footwear 100.

In addition to being effective at preventing soil accumulation, the film116 has also been found to be sufficiently durable for its intended useon the ground-contacting side of the outsole 112. Durability is based onthe nature and strength of the interfacial bond of the film 116 to thebottom surface 144 of the backing plate 136, as well as the physicalproperties of the film 116 itself. For many examples, during the usefullife of the film 116, the film 116 may not delaminate from the backingplate 136, and it can be substantially abrasion- and wear-resistant(e.g., maintaining its structural integrity without rupturing ortearing).

In various embodiments, the useful life of the film 116 (and the outsole112 and footwear 100 containing it) is at least 10 hours, 20 hours, 50hours, 100 hours, 120 hours, or 150 hours of wear. For example, in someapplications, the useful life of the film 116 ranges from 20 hours to120 hours. In other applications, the useful life of the film 116 rangesfrom 50 hours to 100 hours of wear.

Interestingly, for many examples, the dry and wet states of the film 116can allow the film 116 to dynamically adapt in durability to account fordry and wet surface play. For example, when used on a dry ground 166,the film 116 can also be dry, which renders it stiffer and more wearresistant. Alternatively, when used on wet ground 166 or when wetmaterial is present on a dry ground 166, the film 116 can quickly takeup water to achieve a partially or fully saturated condition, which maybe a swollen and/or compliant state. However, the wet ground 166 imposesless wear on the swollen and compliant film 116 compared to dry ground166. As such, the film 116 can be used in a variety of conditions, asdesired. Nonetheless, the footwear 100 and the outsole 112 areparticularly beneficial for use in wet environments, such as with muddysurfaces, grass surfaces, and the like.

While the film 116 is illustrated above in FIGS. 1-4 as extending acrossthe entire bottom surface 144 of the outsole 112 of the footwear 100, inalternative embodiments, the film 116 can alternatively be present asone or more segments that are present at separate, discrete locations onthe bottom surface 144 of the outsole 112. For instance, as shown inFIG. 11, the film 116 can alternatively be present as a first segment116A secured to the bottom surface 144 at the forefoot region 122, suchas in the interstitial region between the traction elements 114 ofcluster 147A; a second segment 116B secured to the bottom surface 144 atthe midfoot region 124, such as in the interstitial region between thetraction elements 114 of cluster 147B; and/or a third segment 116Csecured to the bottom surface 144 at the heel region 126, such as in theinterstitial region between the traction elements 114 of cluster 147C.In each of these examples, the remaining regions of the bottom surface144 can be free of the film 116.

In some arrangements, the film 116 may include one or more segmentssecured to the bottom surface 144 at a region 178 between the clusters147A and 147B, at a region 180 between the clusters 147B and 147C, orboth. For example, the film 116 may include a first segment present onthe bottom surface 144 that encompasses the locations of segment 116A,the region 178, and segment 116B as well at the location of region 178;and a second segment corresponding to the segment 116B (at the cluster147C). As also shown in FIG. 11, the segments of the film 116 (e.g.,segments 116A, 116B, and 116C) can optionally have surface dimensionsthat conform to the overall geometry of the backing plate 136, such asto conform to the contours of the ridges 148, the traction elements 114,and the like.

In another arrangement, the bottom surface 144 may include a front edgeregion 182 between the front edge 128 and the cluster 147A (andoptionally include a front portion of the cluster 147A) that is free ofthe film 116. As some of the examples of the film 116 may be lubriciouswhen partially or fully saturated, having the film 116 present in thefront edge region 182 of the bottom surface 144 can potentially impacttraction and ball handling during sports. Furthermore, soil accumulationis typically most prominent in the interstitial regions of the clusters147A, 147B, and 147C, in comparison to the front edge 128.

Furthermore, the backing plate 136 can also include one or more recessedpockets, such as a pocket 188 shown in FIG. 12, in which the film 116 ora sub-segment of the film 116 can reside. This can potentially increasethe durability of the film 116 by protecting it from lateraldelamination stresses. For instance, the backing plate 136 can include apocket 188 in the interstitial region of cluster 147C, where thesub-segment 116C of the film 116 can be secured to the bottom surface144 within the pocket 188. In this case, the dry-state thickness 160 ofthe film 116 can vary relative to a depth 190 of the pocket 188.

In some embodiments, the depth 190 of the pocket 188 can range from 80%to 120%, from 90% to 110%, or from 95% to 105% of the dry-statethickness 160 of the film 116. Moreover, in embodiments in which thebacking plate 136 includes multiple pockets 188, each pocket 188 mayhave the same depth 190 or the depths 190 may independently vary asdesired. As can be appreciated, the increased bonding of the film 116due to the recessed pocket 188 can potentially reduce the swelling ofthe film 116 when partially or fully saturated. However, a significantportion of the film 116 can be offset enough from the walls of thepocket 188 such that these interfacial bonds (relative to the dry-statethickness 160) will minimally affect the swelling and water-absorbingperformance of the film 116.

FIG. 13 illustrates an alternative design for the engagement between thefilm 116 and the bottom surface 144. In this case, the backing plate 136can include one or more recessed indentations 192 having any suitablepattern(s), and in which portions of the film 116 extend into theindentations 192 to increase the interfacial bond surface area betweenthe film 116 and the bottom surface 144 of the backing plate 136. Forexample, the indentations 192 can be present as one or moregeometrically-shaped holes (e.g., circular, rectangular, or othergeometric shapes) or irregularly-shaped holes in the backing plate 136,one or more trenches or channels extending partially or fully along thebacking plate 136 (in the lateral, longitudinal, or diagonaldirections), and the like.

In these embodiments, the film 116 can have two (or more) thicknessesdepending on whether a given portion of the film 116 extends into one ofthe indentations. For ease of discussion and readability, the dry-statethickness 160 of the film 116, as used herein, refers to a portion ofthe film 116 (in a dry state) that does not extend into one of theindentations, such as at locations 194. As such, the dry-state thickness160 shown in FIG. 13 is the same as the dry-state thickness 160 shownabove in FIG. 5.

Each indentation 192 may independently have a depth 196, which can rangefrom 1% to 200%, from 25% to 150%, or from 50% to 100% of the dry-statethickness 160 of the film 116. In these locations, the dry-statethickness of the film 116 is the sum of the dry-state thickness 160 andthe depth 196. An interesting result of this arrangement is that thefilm 116 can potentially swell to different partially or fullysaturated-state thicknesses 164. In particular, because the amount thatthe film 116 swells depends on the initial, dry-state thickness of thefilm 116, and because the portions of the film 116 at the indentations192 have greater dry-state thicknesses compared to the portions of thefilm 116 at locations 194, this can result in a non-planar swelling ofthe film 116, as depicted by broken lines 198. The particular dimensionsof the non-planar swelling can vary depending on the relative dry-statethicknesses of the film 116, the depth 196 of the indentations 192, theextent of saturation of the film 116, the particular composition of thefilm 116, and the like.

FIG. 14 illustrates a variation on the indentations 192 shown above inFIG. 13. In the design shown in FIG. 14, the indentations 192 can alsoextend in-plane with the backing plate 136 to form locking members 200(e.g., arms or flanged heads). This design can also be produced withco-extrusion or injection molding techniques, and can further assist inmechanically locking the film 116 to the backing plate 136.

As discussed above, the outsole 112 with the film 116 is particularlysuitable for use in global football/soccer applications. However, thefilm 116 can also be used in combination with other types of footwear100, such as for articles of footwear 100 for golf (shown in FIG. 15),for baseball (shown in FIG. 16), and for American football (shown inFIG. 17), each of which can include traction elements 114 as cleats,studs, and the like.

FIG. 15 illustrates an embodiment in which the film 116 is positioned onone or more portions of the outsole 112 and/or cleats 114 in an articleof golf footwear 100. In some cases, the film 116 is present on one ormore locations of the ground-facing surface of the outsole 112 exceptthe cleats 114 (e.g., a non-cleated surface, such as generallyillustrated in FIG. 1 for the global football/soccer footwear 100).Alternatively or additionally, the film 116 can be present as one ormore film segments 116D on one or more surfaces between tread patterns202 on ground-facing surface of the outsole 112.

Alternatively or additionally, the film 116 can be incorporated onto oneor more surfaces of the cleats 114. For example, the film 116 can alsobe on central region of cleat 114 between the shafts/spikes 150A, suchas where each cleat 114 is screwed into or otherwise mounted to theoutsole 112 backing plate 136, and has a generally flat central baseregion 158A (i.e., where the film 116 is located) and threeshafts/spikes 150A arranged around the perimeter of the central region158A.

In such embodiments, remaining regions of the outsole 112 can be free ofthe film 116. For example, the cleats 114 having film 116 can beseparate components that can be secured to the outsole 112 (e.g.,screwed or snapped in), where the outsole 112 itself can be free of thefilm 116. In other words, the film-covered cleats 114 can be provided ascomponents for use with standard footwear not otherwise containing the116 (e.g., golf shoes or otherwise).

FIG. 16 illustrates an embodiment in which the film 116 is positioned onone or more portions of the outsole 112 in an article of baseballfootwear 100. In some cases, the film 116 is present on one or morelocations of the ground-facing surface of the outsole 112 except thecleats 114 (e.g., a non-cleated surface, such as generally illustratedin FIG. 1 for the global football/soccer footwear 100). Alternatively oradditionally, the film 116 can be present as one or more film segments116D on one or more recessed surfaces 204 in the ground-facing surfaceof the outsole 112, which recessed surfaces 204 can include the cleats114 therein (e.g., film 116 is located only in one or more of therecessed surfaces 204, but not substantially on the cleats).

FIG. 17 illustrates an embodiment in which the film 116 is positioned onone or more portions of the outsole 112 in an article of Americanfootball footwear 100. In some cases, the film 116 is present on one ormore locations of the ground-facing surface of the outsole 112 exceptthe cleats 114 (e.g., a non-cleated surface, such as generallyillustrated in FIG. 1 for the global football/soccer footwear 100).Alternatively or additionally, the film 116 can be present as one ormore film segments 116D on one or more recessed surfaces 204 in theground-facing surface of the outsole 112, which recessed surfaces 204can include the cleats 114 therein (e.g., film 116 is located only inone or more of the recessed surfaces 204, but not substantially on thecleats).

FIG. 18 illustrates an embodiment in which the film 116 is positioned onone or more portions of the outsole 112 in an article of hiking footwear100 (e.g., hiking shoes or boots). As illustrated, the traction elements114 are in the form of lugs 114D which are integrally formed with andprotrude from the outsole 112 bottom surface 144. In some cases, thefilm 116 is present on one or more locations of the bottom surface 144of the outsole 112 except the lugs 114D. For example, the film 116 canbe located on recessed surfaces 204 between adjacent lugs 114D (e.g.,but not substantially on the 114D).

The foregoing discussions of footwear 100 and outsole 112 have been madeabove in the context of footwear having traction elements (e.g.,traction elements 114), such as cleats, studs, spikes, lugs, and thelike. However, footwear 100 having film 116 can also be designed for anysuitable activity, such as running, track and field, rugby, cycling,tennis, and the like. In these embodiments, one or more segments of thefilm 116 are preferably located in interstitial regions between thetraction elements, such as in the interstitial grooves of a running shoetread pattern.

As discussed above, the outsole films of the present disclosure, such asthe film 116 for use with outsole 112 (and footwear 100), cancompositionally include a film material that allows the outsole film totake up water. As used herein, the terms “take up”, “taking up”,“uptake”, “uptaking”, and the like refer to the drawing of a liquid(e.g., water) from an external source into the film, such as byabsorption, adsorption, or both. Furthermore, as briefly mentionedabove, the term “water” refers to an aqueous liquid that can be purewater, or can be an aqueous carrier with lesser amounts of dissolved,dispersed or otherwise suspended materials (e.g., particulates, otherliquids, and the like).

The ability of the outsole film (e.g., the film 116) to uptake water andto correspondingly swell and increase in compliance can reflect itsability to prevent soil accumulation during use with an article offootwear (e.g., footwear 100). As discussed above, when the outsole filmtakes up water (e.g., through absorption, adsorption, capillary action,etc. . . . ), the water taken up by the outsole film transitions theoutsole film from a dry, relatively more rigid state to a partially orfully saturated state that is relatively more compliant. When theoutsole film is then subjected to an application of pressure, eithercompressive or flexing, the outsole film can reduce in volume, such asto expel at least a portion of its water.

This expelled water is believed to reduce the adhesive/cohesive forcesof soil particles at the outsole, which taken alone, or more preferablyin combination with the film compliance, can prevent or otherwise reducesoil accumulation at the outsole. Accordingly, the outsole film canundergo dynamic transitions during and between foot strikes, such aswhile a wearer is running or walking, and these dynamic transitions canresult in forces which dislodge accumulated soil or otherwise reducesoil accumulation on the outsole as well.

Based on the multiple interacting mechanisms involved in reducing orpreventing soil accumulation on the outsoles of the present disclosure,it has been found that different properties can be good at predictingsoil-shedding performance. For instance, the article of footwear of thepresent disclosure (e.g., the footwear 100), the outsole (e.g., theoutsole 114), and the outsole film (e.g., the film 116) can becharacterized in terms of the outsole film's water uptake capacity andrate, swell capacity, contact angle when wet, coefficient of frictionwhen wet and dry, reduction in storage modulus from dry to wet,reduction in glass transition temperature from dry to wet, and the like.

The terms “Footwear Sampling Procedure”, “Co-Extruded Film SamplingProcedure”, “Neat Film Sampling Procedure”, “Neat Material SamplingProcedure”, “Water Uptake Capacity Test”, “Water Uptake Rate Test”,“Swelling Capacity Test”, “Contact Angle Test”, “Coefficient of FrictionTest”, “Storage Modulus Test”, “Glass Transition Temperature Test”,“Impact Energy Test”, and “Soil Shedding Footwear Test” as used hereinrefer to the respective sampling procedures and test methodologiesdescribed in the Property Analysis And Characterization Proceduresection below. These sampling procedures and test methodologiescharacterize the properties of the recited materials, films, outsoles,footwear, and the like, and are not required to be performed as activesteps in the claims.

For example, in some aspects, the outsole film as secured to a footwearoutsole has a water uptake capacity at 24 hours greater than 40% byweight, as characterized by the Water Uptake Capacity Test with theFootwear Sampling Procedure, each as described below. It is believedthat if a particular outsole film is not capable of taking up greaterthan 40% by weight in water within a 24-hour period, either due to itswater uptake rate being too slow, or its ability to take up water is toolow (e.g., due to its thinness, not enough material may be present, orthe overall capacity of the material to take up water is too low), thenthe outsole film will not be effective in preventing or reducing soilaccumulation.

In further aspects, the outsole film as secured to a footwear outsolehas a water uptake capacity at 24 hours greater than 50% by weight,greater than 100% by weight, greater than 150% by weight, or greaterthan 200% by weight. In other aspects, the outsole film as secured to afootwear outsole has a water uptake capacity at 24 hours less than 900%by weight, less than 750% by weight, less than 600% by weight, or lessthan 500% by weight.

In some particular aspects, the outsole film as secured to a footwearoutsole has a water uptake capacity at 24 hours ranging from 40% byweight to 900% by weight. For example, the outsole film can have a wateruptake capacity ranging from 100% by weight to 900% by weight, from 100%by weight to 750% by weight, from 100% by weight to 700% by weight, from150% by weight to 600% by weight, from 200% by weight to 500% by weight,or from 300% by weight to 500% by weight.

These water uptake capacities are determined by the Water UptakeCapacity Test with the Footwear Sampling Procedure, and can apply tosamples taken at any suitable representative location along the outsole,where the samples may be acquired pursuant to the Footwear SamplingProcedure. In some cases, samples can be taken from one or more of theforefoot region, the midfoot region, and/or the heel region; from eachof the forefoot region, the midfoot region, and the heel region; fromwithin one or more of the traction element clusters (between thetraction elements) at the forefoot region, the midfoot region, and/orthe heel region; from of the traction element clusters; on planarregions of the traction elements (for embodiments in which the outsolefilm is present on the traction elements), and combinations thereof.

As discussed below, the water uptake capacity of the outsole film canalternatively be measured in a simulated environment with the outsolefilm co-extruded with a backing substrate. The backing substrate can beproduced from any suitable material that is compatible with the outsolefilm, such as a material used to form an outsole backing plate. As such,suitable water uptake capacities at 24 hours for the outsole film asco-extruded with a backing substrate, as characterized by the WaterUptake Capacity Test with the Co-extruded Film Sampling Procedure,include those discussed above for the Water Uptake Capacity Test withthe Footwear Sampling Procedure.

Additionally, it has been found that when the outsole film is secured toanother surface, such as being thermally or adhesively bonded to anoutsole substrate (e.g., an outsole backing plate), the interfacial bondformed between the outsole film and the outsole substrate can restrictthe extent that the outsole film can take up water and/or swell. Assuch, it is believed that the outsole film as bonded to an outsolesubstrate or co-extruded backing substrate can potentially have a lowerwater uptake capacity and/or a lower swell capacity compared to the sameoutsole film in a neat film form or a neat material form.

As such, the water uptake capacity and the water uptake rate of theoutsole film can also be characterized based on the outsole film in neatform (i.e., an isolated film that is not bonded to another material).The outsole film in neat form can have a water uptake capacity at 24hours greater than 40% by weight, greater than 100% by weight, greaterthan 300% by weight, or greater than 1000% by weight, as characterizedby the Water Uptake Capacity Test with the Neat Film Sampling Procedure.The outsole film in neat form can also have a water uptake capacity at24 hours less than 900% by weight, less than 800% by weight, less than700% by weight, less than 600% by weight, or less than 500% by weight.

In some particular aspects, the outsole film in neat form has a wateruptake capacity at 24 hours ranging from 40% by weight to 900% byweight, from 150% by weight to 700% by weight, from 200% by weight to600% by weight, or from 300% by weight to 500% by weight.

The outsole film as secured to a footwear outsole (or other footwearcomponent) may also have a water uptake rate greater than 20grams/(meter²-minutes^(1/2)), as characterized by the Water Uptake RateTest with the Footwear Sampling Procedure. As discussed above, in someaspects, the outsole film (e.g., the film 116) can take up water betweenthe compressive cycles of foot strikes, which is believed to at leastpartially replenish the outsole film between the foot strikes.

As such, in further aspects, the outsole film as secured to a footwearoutsole has a water uptake rate greater than 20grams/(meter²-minutes^(1/2)), greater than 100grams/(meter²-minutes^(1/2)), greater than 200grams/(meter²-minutes^(1/2)), greater than 400grams/(meter²-minutes^(1/2)), or greater than 600grams/(meter²-minutes^(1/2)). In some particular embodiments, theoutsole film as secured to a footwear outsole has a water uptake rateranging from 1 to 1,500 grams/(meter²-minutes^(1/2)), 20 to 1,300grams/(meter²-minutes^(1/2)), from 30 to 1,200grams/(meter²-minutes^(1/2)), from 30 to 800grams/(meter²-minutes^(1/2)), from 100 to 800grams/(meter²-minutes^(1/2)), from 100 to 600grams/(meter²-minutes^(1/2)), from 150 to 450grams/(meter²-minutes^(1/2)), from 200 to 1,000grams/(meter²-minutes^(1/2)), from 400 to 1,000grams/(meter²-minutes^(1/2)), or from 600 to 900grams/(meter²-minutes^(1/2)).

Suitable water uptake rates for the outsole film as secured to aco-extruded backing substrate, as characterized by the Water Uptake RateTest with the Co-extruded Film Sampling Procedure, and as provided inneat form, as characterized by the Water Uptake Rate Test with the NeatFilm Sampling Procedure, each include those discussed above for theWater Uptake Rate Test with the Footwear Sampling Procedure.

In certain aspects, the outsole film as secured to a footwear outsolecan also swell, increasing the film's thickness and/or volume, due towater uptake. This swelling of the outsole film can be a convenientindicator showing that the outsole film is taking up water, and canassist in rendering the outsole film compliant. In some aspects, theoutsole film as secured to a footwear outsole has an increase in filmthickness (or swell thickness increase) at 1 hour of greater than 20% orgreater than 50%, for example ranging from 30% to 350%, from 50% to400%, from 50% to 300%, from 100% to 300%, from 100% to 200%, or from150% to 250%, as characterized by the Swelling Capacity Test with theFootwear Sampling Procedure. In some further aspects, the outsole filmas secured to a footwear outsole has an increase in film thickness at 24hours ranging from 45% to 400%, from 100% to 350%, or from 150% to 300%.

Additionally, the outsole film as secured to a footwear outsole can havean increase in film volume (or volumetric swell increase) at 1 hour ofgreater than 50%, for example ranging from 10% to 130%, from 30% to100%, or from 50% to 90%. Moreover, the outsole film as secured to afootwear outsole can have an increase in film volume at 24 hours rangingfrom 25% to 200%, from 50% to 150%, or from 75% to 100%.

For co-extruded film simulations, suitable increases in film thicknessand volume at 1 hour and 24 hours for the outsole film as secured to aco-extruded backing substrate, as characterized by the Swelling CapacityTest with the Co-extruded Film Sampling Procedure, include thosediscussed above for the Swelling Capacity Test with the FootwearSampling Procedure.

The outsole film in neat form can have an increase in film thickness at1 hour ranging from 35% to 400%, from 50% to 300%, or from 100% to 200%,as characterized by the Swelling Capacity Test with the Neat FilmSampling Procedure. In some further embodiments, the outsole film inneat form can have an increase in film thickness at 24 hours ranging 45%to 500%, from 100% to 400%, or from 150% to 300%. Correspondingly, theoutsole film in neat form can have an increase in film volume at 1 hourranging from 50% to 500%, from 75% to 400%, or from 100% to 300%.

As also discussed above, in some aspects, the surface of the outsolefilm preferably exhibits hydrophilic properties. The hydrophilicproperties of the outsole film surface can be characterized bydetermining the static sessile drop contact angle of the film's surface.Accordingly, in some examples, the outsole film in a dry state has astatic sessile drop contact angle (or dry-state contact angle) of lessthan 105°, or less than 95°, less than 85°, as characterized by theContact Angle Test (independent of film sampling process). In somefurther examples, the outsole film in a dry state has a static sessiledrop contact angle ranging from 60° to 100°, from 70° to 100°, or from65° to 95°.

In other examples, the outsole film in a saturated state has a staticsessile drop contact angle (or wet-state contact angle) of less than90°, less than 80°, less than 70°, or less than 60°. In some furtherexamples, the outsole film in a saturated state has a static sessiledrop contact angle ranging from 45° to 75°. In some cases, the dry-statestatic sessile drop contact angle of the outsole film surface is greaterthan the wet-state static sessile drop contact angle of the outsole filmsurface by at least 10°, at least 15°, or at least 20°, for example from10° to 40°, from 10° to 30°, or from 10° to 20°.

The surface of the outsole film (and of the outsole in general) can alsoexhibit a low coefficient of friction when the outsole film partiallyfor fully saturated. Examples of suitable coefficients of friction forthe outsole film in a dry state (or dry-state coefficient of friction)are less than 1.5, for instance ranging from 0.3 to 1.3, or from 0.3 to0.7, as characterized by the Coefficient of Friction Test (independentof film sampling process). Examples of suitable coefficients of frictionfor the outsole film in a saturated state (or wet-state coefficient offriction) are less than 0.8 or less than 0.6, for instance ranging from0.05 to 0.6, from 0.1 to 0.6, or from 0.3 to 0.5. Furthermore, theoutsole film can exhibit a reduction in its coefficient of friction fromits dry state to its saturated state, such as a reduction ranging from15% to 90%, or from 50% to 80%. In some cases, the dry-state coefficientof friction is greater than the wet-state coefficient of friction forthe outsole film, for example being higher by a value of at least 0.3 or0.5, such as 0.3 to 1.2 or 0.5 to 1.

Furthermore, the compliance of the outsole film can be characterized byits storage modulus in the dry state (when equilibrated at 0% relativehumidity (RH)), in a partially wetted state (e.g., when equilibrated at50% RH), and in a wetted state (when equilibrated at 90% RH), and byreductions in its storage modulus between the dry and saturated states.In particular, the outsole film can have a reduction in storage modulus(ΔE′) from the dry state relative to the wetted state. A reduction instorage modulus as the water concentration in the outsole film increasescorresponds to an increase in compliance, because less stress isrequired for a given strain/deformation.

In some embodiments, the outsole film exhibits a reduction in thestorage modulus from its dry state to its saturated state of more than20%, more than 40%, more than 60%, more than 75%, more than 90%, or morethan 99%, relative to the storage modulus in the dry state, and ascharacterized by the Storage Modulus Test with the Neat Film SamplingProcess or the Neat Material Sampling Process.

In some further embodiments, the dry-state storage modulus of theoutsole film is greater than its wet-state (or saturated-state) storagemodulus by more than 25 megaPascals (MPa), by more than 50 MPa, by morethan 100 MPa, by more than 300 MPa, or by more than 500 MPa, for exampleranging from 25 MPa to 800 MPa, from 50 MPa to 800 MPa, from 100 MPa to800 MPa, from 200 MPa to 800 MPa, from 400 MPa to 800 MPa, from 25 MPato 200 MPa, from 25 MPa to 100 MPa, or from 50 MPa to 200 MPa.Additionally, the dry-state storage modulus can range from 40 MPa to 800MPa, from 100 MPa to 600 MPa, or from 200 MPa to 400 MPa, ascharacterized by the Storage Modulus Test. Additionally, the wet-statestorage modulus can range from 0.003 MPa to 100 MPa, from 1 MPa to 60MPa, or from 20 MPa to 40 MPa.

In addition to a reduction in storage modulus, the outsole film (or acrosslinked polymeric material on an outsole external surface) can alsoexhibit a reduction in its glass transition temperature from the drystate (when equilibrated at 0% relative humidity (RH) to the wettedstate (when equilibrated at 90% RH). While not wishing to be bound bytheory, it is believed that the water taken up by the outsole filmplasticizes the outsole film, which reduces its storage modulus and itsglass transition temperature, rendering the outsole film more compliant(e.g., compressible, expandable, and stretchable).

In some embodiments, the outsole film can exhibit a reduction in glasstransition temperature (ΔT_(g)) from its dry-state glass transitiontemperature to its wet-state glass transition temperature of more than a5° C. difference, more than a 6° C. difference, more than a 10° C.difference, or more than a 15° C. difference, as characterized by theGlass Transition Temperature Test with the Neat Film Sampling Process orthe Neat Material Sampling Process. For instance, the reduction in glasstransition temperature (ΔT_(g)) can range from more than a 5° C.difference to a 40° C. difference, from more than a 6° C. difference toa 50° C. difference, form more than a 10° C. difference to a 30° C.difference, from more than a 30° C. difference to a 45° C. difference,or from a 15° C. difference to a 20° C. difference. The outsole film canalso exhibit a dry glass transition temperature ranging from −40° C. to−80° C., or from −40° C. to −60° C.

Alternatively (or additionally), the reduction in glass transitiontemperature (ΔT_(g)) can range from a 5° C. difference to a 40° C.difference, form a 10° C. difference to a 30° C. difference, or from a15° C. difference to a 20° C. difference. The outsole film can alsoexhibit a dry glass transition temperature ranging from −40° C. to −80°C., or from −40° C. to −60° C.

In some further aspects, the outsole film can exhibit a soil sheddingability with a relative impact energy ranging from 0 to 0.9, from 0.2 to0.7, or from 0.4 to 0.5, as characterized by the Impact Energy Test withthe Co-extruded Film Sampling Procedure. Moreover, the outsole film(e.g., the film 116) is preferably durable enough, and has a sufficientbond to the outsole backing plate, for use over extended durations ingame play. For instance, it has been found that the outsole film of thepresent disclosure can, in some aspects, continue to perform withoutsignificant visual abrasion or delamination for more than 80 or 100hours, as discussed above.

In particular embodiments, the film material for the outsole filmcompositionally includes a hydrogel and, optionally, one or moreadditives. As used herein, the term “hydrogel” refers to a polymericmaterial that is capable of taking up at least 10% by weight in water,based on a dry weight of the polymeric material. The hydrogel caninclude a crosslinked or crosslinkable polymeric network, wherecrosslinks interconnect multiple polymer chains to form the polymericnetwork, and where the crosslinks can be physical crosslinks, covalentcrosslinks, or can include both physical and covalent crosslinks (withinthe same polymeric network). The hydrogel constitutes more than 50% byweight of the entire film material for the outsole film, or more than75% by weight, or more 85% by weight, or more than 95% by weight. Insome aspects, the film material of the outsole film consists essentiallyof the hydrogel.

For a physical crosslink, a copolymer chain can form entangled regionsand/or crystalline regions through non-covalent (non-bonding)interactions, such as, for example, an ionic bond, a polar bond, and/ora hydrogen bond. In particular, the crystalline regions create thephysical crosslink between the copolymer chains whereas the non-bondinginteractions form the crystalline domains (which include hard segments,as described below). These hydrogels can exhibit sol-gel reversibility,allowing them to function as thermoplastic polymers, which can beadvantageous for manufacturing and recyclability. As such, in somepreferred embodiments, the hydrogel of the film material includes aphysically crosslinked polymeric network to function as a thermoplastichydrogel.

The physically crosslinked hydrogels can be characterized by hardsegments and soft segments, which can exist as phase separated regionswithin the polymeric network while the film material is in a solid(non-molten) state. The hard segments can form portions of the polymerchain backbones, and can exhibit high polarities, allowing the hardsegments of multiple polymer chains to aggregate together, or interactwith each other, to form semi-crystalline regions of the polymericnetwork.

A “semi-crystalline” or “crystalline” region has an ordered molecularstructure with sharp melt points, which remains solid until a givenquantity of heat is absorbed and then rapidly changes into a lowviscosity liquid. A “pseudo-crystalline” region has properties of acrystal, but does not exhibit a true crystalline diffraction pattern.For ease of reference, the term “crystalline region” will be used hereinto collectively refer to a crystalline region, a semi-crystallineregion, and a pseudo-crystalline region of a polymeric network.

In comparison, the soft segments can be longer, more flexible,untwistable, hydrophilic regions of the polymeric network that allow thepolymer network to expand and swell under the pressure of taken upwater. The soft segments can constitute amorphous hydrophilic regions ofthe hydrogel or crosslinked polymeric network. The soft segments, oramorphous regions, can also form portions of the backbones of thepolymer chains along with the hard segments. Additionally, one or moreportions of the soft segments, or amorphous regions, can be grafted orotherwise extend as pendant chains that extend from the backbones at thesoft segments. The soft segments, or amorphous regions, can becovalently bonded to the hard segments, or crystalline regions (e.g.,through carbamate linkages). For example, a plurality of amorphoushydrophilic regions can be covalently bonded to the crystalline regionsof the hard segments.

Thus, in various embodiments, the hydrogel or crosslinked polymericnetwork includes a plurality of copolymer chains wherein at least aportion of the copolymer chains each comprise a hard segment physicallycrosslinked to other hard segments of the copolymer chains and a softsegment covalently bonded to the hard segment, such as through acarbamate group or an ester group. In some cases, the hydrogel, orcrosslinked polymeric network, includes a plurality of copolymer chainswherein at least a portion of the copolymer chains each comprise a firstchain segment physically crosslinked to at least one other copolymerchain of the plurality of copolymer chains and a hydrophilic segment(e.g., a polyether chain segment) covalently bonded to the first chainsegment, such as through a carbamate group or an ester group.

In various embodiments, the hydrogel or crosslinked polymeric networkincludes a plurality of copolymer chains, wherein at least a portion ofthe copolymer chains each include a first segment forming at least acrystalline region with other hard segments of the copolymer chains; anda second segment, such as a soft segment (e.g., a segment havingpolyether chains or one or more ether groups) covalently bonded to thefirst segment, where the soft segment forms amorphous regions of thehydrogel or crosslinked polymeric network. In some cases, the hydrogelor crosslinked polymeric network includes a plurality of copolymerchains, where at least a portion of the copolymer chains havehydrophilic segments.

The soft segments, or amorphous regions, of the copolymer chains canconstitute a substantial portion of the polymeric network, allowingtheir hydrophilic segments or groups to attract water molecules. In someembodiments, the soft segments, or amorphous regions, are present in thecopolymer chains in a ratio (relative to the hard segments, orcrystalline regions) that is at least or greater than 20:1 by weight,that ranges from 20:1 to 110:1 by weight, or from 40:1 to 110:1 byweight, or from 40:1 to 80:1 by weight, or from 60:1 to 80:1.

For a covalent crosslink, one polymer chain is linked to one or moreadditional polymer chains with one or more covalent bonds, typicallywith a linking segment or chain. Covalently crosslinked hydrogels (e.g.,thermoset and photocured hydrogels) can be prepared by covalentlylinking the polymer chains together using one or more multi-functionalcompounds, such as, for example, a molecule having at least twoethylenically-unsaturated groups, at least two oxirane groups (e.g.,diepoxides), or combinations thereof (e.g., glycidyl methacrylate); andcan also include any suitable intermediate chain segment, such as C₁₋₃₀,C₂₋₂₀, or C₂₋₁₀ hydrocarbon, polyether, or polyester chain segments.

The multi-functional compounds can include at least three functionalgroups selected from the group consisting of isocyanidyl, hydroxyl,amino, sulfhydryl, carboxyl or derivatives thereof, and combinationsthereof. In some embodiments, such as when the polymer network includespolyurethane, the multi-functional compound can be a polyol having threeor more hydroxyl groups (e.g., glycerol, trimethylolpropane,1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane) or apolyisocyanate having three or more isocyanate groups. In some cases,such as when the polymer network includes polyamide, themulti-functional compound can include, for example, carboxylic acids oractivated forms thereof having three or more carboxyl groups (oractivated forms thereof, polyamines having three or more amino groups,and polyols having three or more hydroxyl groups (e.g., glycerol,trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, andtrimethylolethane). In various cases, such as when the polymer networkincludes polyolefin, the multi-functional compound can be a compoundhaving two ethylenically-unsaturated groups.

It has been found that the crosslinking density of the crosslinkedhydrogel can impact the structural integrity and water uptake capacitiesof the outsole film (e.g., the film 116). If the crosslinking density istoo high, the resulting outsole film can be stiff and less compliant,which can reduce its water uptake and swelling capacity. On the otherhand, if the crosslinking density is too low, then the resulting outsolefilm can lose its structural integrity when saturated. As such, thehydrogel(s) of the film material preferably have a balanced crosslinkingdensity such that the outsole film retains its structural integrity, yetis also sufficiently compliant when partially or fully saturated withwater.

The crosslinked polymer network of the hydrogel for the outsole film(e.g., the film 116) can include any suitable polymer chains thatprovide the desired functional properties (e.g., water uptake, swelling,and more generally, preventing soil accumulation), and also desirablyprovide good durability for the outsole. For example, the hydrogel canbe based on one or more polyurethanes, one or more polyamides, one ormore polyolefins, and combinations thereof (e.g., a hydrogel based onpolyurethane(s) and polyamide(s)). In these embodiments, the hydrogel orcrosslinked polymeric network can include a plurality of copolymerchains wherein at least a portion of the copolymer chains each include apolyurethane segment, a polyamide segment, or a combination thereof. Insome embodiments, the one or more polyurethanes, one or more polyamides,one or more polyolefins, and combinations thereof include polysiloxanesegments and/or ionomer segments.

In some embodiments, the hydrogel includes a crosslinked polymericnetwork with one or more polyurethane copolymer chains (i.e., aplurality of polyurethane chains) that are physically and/or covalentlycrosslinked (referred to as a “polyurethane hydrogel”). The polyurethanehydrogel can be produced by polymerizing one or more isocyanates withone or more polyols to produce copolymer chains having carbamatelinkages (—N(CO)O—) as illustrated below in Formula 1, where theisocyanate(s) each preferably include two or more isocyanate (—NCO)groups per molecule, such as 2, 3, or 4 isocyanate groups per molecule(although, single-functional isocyanates can also be optionallyincluded, e.g., as chain terminating units).

In these embodiments, each R₁ independently is an aliphatic or aromaticsegment, and each R₂ is a hydrophilic segment.

Unless otherwise indicated, any of the functional groups or chemicalcompounds described herein can be substituted or unsubstituted. A“substituted” group or chemical compound, such as an alkyl, alkenyl,alkynyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, alkoxyl, ester,ether, or carboxylic ester refers to an alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkenyl, aryl, heteroaryl, alkoxyl, ester, ether, orcarboxylic ester group, has at least one hydrogen radical that issubstituted with a non-hydrogen radical (i.e., a substitutent). Examplesof non-hydrogen radicals (or substituents) include, but are not limitedto, alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, ether, aryl,heteroaryl, heterocycloalkyl, hydroxyl, oxy (or oxo), alkoxyl, ester,thioester, acyl, carboxyl, cyano, nitro, amino, amido, sulfur, and halo.When a substituted alkyl group includes more than one non-hydrogenradical, the substituents can be bound to the same carbon or two or moredifferent carbon atoms.

Additionally, the isocyanates can also be chain extended with one ormore chain extenders to bridge two or more isocyanates. This can producepolyurethane copolymer chains as illustrated below in Formula 2, whereinR₃ includes the chain extender.

Each segment R₁, or the first segment, in Formulas 1 and 2 canindependently include a linear or branched C₃₋₃₀ segment, based on theparticular isocyanate(s) used, and can be aliphatic, aromatic, orinclude a combination of aliphatic portions(s) and aromatic portion(s).The term “aliphatic” refers to a saturated or unsaturated organicmolecule that does not include a cyclically conjugated ring systemhaving delocalized pi electrons. In comparison, the term “aromatic”refers to a cyclically conjugated ring system having delocalized pielectrons, which exhibits greater stability than a hypothetical ringsystem having localized pi electrons.

In aliphatic embodiments (from aliphatic isocyanate(s)), each segment R₁can include a linear aliphatic group, a branched aliphatic group, acycloaliphatic group, or combinations thereof. For instance, eachsegment R₁ can include a linear or branched C₃₋₂₀ alkylene segment(e.g., C₄₋₁₅ alkylene or C₆₋₁₀ alkylene), one or more C₃₋₈ cycloalkylenesegments (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cycloheptyl, or cyclooctyl), and combinations thereof.

Examples of suitable aliphatic diisocyanates for producing thepolyurethane copolymer chains include hexamethylene diisocyanate (HDI),isophorone diisocyanate (IPDI), butylene diisocyanate (BDI),bisisocyanatocyclohexylmethane (HMDI), 2,2,4-trimethylhexamethylenediisocyanate (TMDI), bisisocyanatomethylcyclohexane,bisisocyanatomethyltricyclodecane, norbornane diisocyanate (NDI),cyclohexane diisocyanate (CHDI), 4,4′-dicyclohexylmethane diisocyanate(H12MDI), diisocyanatododecane, lysine diisocyanate, and combinationsthereof.

In aromatic embodiments (from aromatic isocyanate(s)), each segment R₁can include one or more aromatic groups, such as phenyl, naphthyl,tetrahydronaphthyl, phenanthrenyl, biphenylenyl, indanyl, indenyl,anthracenyl, and fluorenyl. Unless otherwise indicated, an aromaticgroup can be an unsubstituted aromatic group or a substituted aromaticgroup, and can also include heteroaromatic groups. “Heteroaromatic”refers to monocyclic or polycyclic (e.g., fused bicyclic and fusedtricyclic) aromatic ring systems, where one to four ring atoms areselected from oxygen, nitrogen, or sulfur, and the remaining ring atomsare carbon, and where the ring system is joined to the remainder of themolecule by any of the ring atoms. Examples of suitable heteroarylgroups include pyridyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl,imidazolyl, thiazolyl, tetrazolyl, oxazolyl, isooxazolyl, thiadiazolyl,oxadiazolyl, furanyl, quinolinyl, isoquinolinyl, benzoxazolyl,benzimidazolyl, and benzothiazolyl.

Examples of suitable aromatic diisocyanates for producing thepolyurethane copolymer chains include toluene diisocyanate (TDI), TDIadducts with trimethyloylpropane (TMP), methylene diphenyl diisocyanate(MDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate(TMXDI), hydrogenated xylene diisocyanate (HXDI), naphthalene1,5-diisocyanate (NDI), 1,5-tetrahydronaphthalene diisocyanate,para-phenylene diisocyanate (PPDI), 3,3′-dimethyldiphenyl-4,4′-diisocyanate (DDDI), 4,4′-dibenzyl diisocyanate (DBDI),4-chloro-1,3-phenylene diisocyanate, and combinations thereof. In someembodiments, the copolymer chains are substantially free of aromaticgroups.

In some preferred embodiments, the polyurethane copolymer chains areproduced from diisocynates including HMDI, TDI, MDI, H₁₂ aliphatics, andcombinations thereof.

Examples of suitable triisocyanates for producing the polyurethanecopolymer chains include TDI, HDI, and IPDI adducts withtrimethyloylpropane (TMP), uretidiones (i.e., dimerized isocyanates),polymeric MDI, and combinations thereof.

Segment R₃ in Formula 2 can include a linear or branched C₂-C₁₀ segment,based on the particular chain extender polyol used, and can be, forexample, aliphatic, aromatic, or polyether. Examples of suitable chainextender polyols for producing the polyurethane copolymer chains includeethylene glycol, lower oligomers of ethylene glycol (e.g., diethyleneglycol, triethylene glycol, and tetraethylene glycol), 1,2-propyleneglycol, 1,3-propylene glycol, lower oligomers of propylene glycol (e.g.,dipropylene glycol, tripropylene glycol, and tetrapropylene glycol),1,4-butylene glycol, 2,3-butylene glycol, 1,6-hexanediol,1,8-octanediol, neopentyl glycol, 1,4-cyclohexanedimethanol,2-ethyl-1,6-hexanediol, 1-methyl-1,3-propanediol,2-methyl-1,3-propanediol, dihydroxyalkylated aromatic compounds (e.g.,bis(2-hydroxyethyl) ethers of hydroquinone and resorcinol,xylene-α,α-diols, bis(2-hydroxyethyl) ethers of xylene-α, α-diols, andcombinations thereof.

Segment R₂ in Formula 1 and 2 can include polyether, polyester,polycarbonate, an aliphatic group, or an aromatic group, wherein thealiphatic group or aromatic group is substituted with one or morependant hydrophilic groups selected from the group consisting ofhydroxyl, polyether, polyester, polylactone (e.g., polyvinylpyrrolidone(PVP)), amino, carboxylate, sulfonate, phosphate, ammonium (e.g.,tertiary and quaternary ammonium), zwitterion (e.g., a betaine, such aspoly(carboxybetaine (pCB) and ammonium phosphonates such asphosphatidylcholine), and combinations thereof. Therefore, thehydrophilic segment of R₂ can form portions of the hydrogel backbone, orbe grafted to the hydrogel backbone as a pendant group. In someembodiments, the pendant hydrophilic group or segment is bonded to thealiphatic group or aromatic group through a linker. Each segment R₂ canbe present in an amount of 5% to 85% by weight, from 5% to 70% byweight, or from 10% to 50% by weight, based on the total weight of thereactant monomers.

In some embodiments, at least one R₂ segment includes a polyethersegment (i.e., a segment having one or more ether groups). Suitablepolyethers include, but are not limited to polyethylene oxide (PEO),polypropylene oxide (PPO), polytetrahydrofuran (PTHF),polytetramethylene oxide (PTMO), and combinations thereof. The term“alkyl” as used herein refers to straight chained and branched saturatedhydrocarbon groups containing one to thirty carbon atoms, for example,one to twenty carbon atoms, or one to ten carbon atoms. The term C_(n)means the alkyl group has “n” carbon atoms. For example, C₄ alkyl refersto an alkyl group that has 4 carbon atoms. C₁₋₇ alkyl refers to an alkylgroup having a number of carbon atoms encompassing the entire range(i.e., 1 to 7 carbon atoms), as well as all subgroups (e.g., 1-6, 2-7,1-5, 3-6, 1, 2, 3, 4, 5, 6, and 7 carbon atoms). Nonlimiting examples ofalkyl groups include, methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl (2-methylpropyl), t-butyl (1,1-dimethylethyl),3,3-dimethylpentyl, and 2-ethylhexyl. Unless otherwise indicated, analkyl group can be an unsubstituted alkyl group or a substituted alkylgroup.

In some cases, at least one R₂ segment includes a polyester segment. Thepolyester can be derived from the polyesterification of one or moredihydric alcohols (e.g., ethylene glycol, 1,3-propylene glycol,1,2-propylene glycol, 1,4-butanediol, 1,3-butanediol,2-methylpentanediol-1,5, diethylene glycol, 1,5-pentanediol,1,5-hexanediol, 1,2-dodecanediol, cyclohexanedimethanol, andcombinations thereof) with one or more dicarboxylic acids (e.g., adipicacid, succinic acid, sebacic acid, suberic acid, methyladipic acid,glutaric acid, pimelic acid, azelaic acid, thiodipropionic acid andcitraconic acid and combinations thereof). The polyester also can bederived from polycarbonate prepolymers, such as poly(hexamethylenecarbonate) glycol, poly(propylene carbonate) glycol, poly(tetramethylenecarbonate)glycol, and poly(nonanemethylene carbonate) glycol. Suitablepolyesters can include, for example, polyethylene adipate (PEA),poly(1,4-butylene adipate), poly(tetramethylene adipate),poly(hexamethylene adipate), polycaprolactone, polyhexamethylenecarbonate, poly(propylene carbonate), poly(tetramethylene carbonate),poly(nonanemethylene carbonate), and combinations thereof.

In various cases, at least one R₂ segment includes a polycarbonatesegment. The polycarbonate can be derived from the reaction of one ormore dihydric alcohols (e.g., ethylene glycol, 1,3-propylene glycol,1,2-propylene glycol, 1,4-butanediol, 1,3-butanediol,2-methylpentanediol-1,5, diethylene glycol, 1,5-pentanediol,1,5-hexanediol, 1,2-dodecanediol, cyclohexanedimethanol, andcombinations thereof) with ethylene carbonate.

In various embodiments, at least one R₂ segment includes an aliphaticgroup substituted with one or more hydrophilic groups selected from thegroup consisting of hydroxyl, polyether, polyester, polylactone (e.g.,polyvinylpyrrolidone), amino, carboxylate, sulfonate, phosphate,ammonium (e.g., tertiary and quaternary ammonium), zwitterion (e.g., abetaine, such as poly(carboxybetaine (pCB) and ammonium phosphonatessuch as phosphatidylcholine), and combinations thereof. In someembodiments, the aliphatic group is linear and can include, for example,a C₁₋₂₀ alkylene chain or a C₁₋₂₀ alkenylene chain (e.g., methylene,ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene,nonylene, decylene, undecylene, dodecylene, tridecylene, ethenylene,propenylene, butenylene, pentenylene, hexenylene, heptenylene,octenylene, nonenylene, decenylene, undecenylene, dodecenylene,tridecenylene). The term “alkylene” refers to a bivalent hydrocarbon.The term C_(n) means the alkylene group has “n” carbon atoms. Forexample, C₁₋₆alkylene refers to an alkylene group having, e.g., 1, 2, 3,4, 5, or 6 carbon atoms. The term “alkenylene” refers to a bivalenthydrocarbon having at least one double bond.

In some cases, at least one R₂ segment includes an aromatic groupsubstituted with one or more hydrophilic groups selected from the groupconsisting of hydroxyl, polyether, polyester, polylactone (e.g.,polyvinylpyrrolidone), amino, carboxylate, sulfonate, phosphate,ammonium (e.g., tertiary and quaternary ammonium), zwitterion (e.g., abetaine, such as poly(carboxybetaine (pCB) and ammonium phosphonatessuch as phosphatidylcholine), and combinations thereof. Suitablearomatic groups include, but are not limited to, phenyl, naphthyl,tetrahydronaphthyl, phenanthrenyl, biphenylenyl, indanyl, indenyl,anthracenyl, fluorenylpyridyl, pyrazinyl, pyrimidinyl, pyrrolyl,pyrazolyl, imidazolyl, thiazolyl, tetrazolyl, oxazolyl, isooxazolyl,thiadiazolyl, oxadiazolyl, furanyl, quinolinyl, isoquinolinyl,benzoxazolyl, benzimidazolyl, and benzothiazolyl.

The aliphatic and aromatic groups are substituted with an appropriatenumber of pendant hydrophilic and/or charged groups so as to provide theresulting hydrogel with the properties described herein. In someembodiments, the pendant hydrophilic group is one or more (e.g., 2, 3,4, 5, 6, 7, 8, 9, 10 or more) hydroxyl groups. In various embodiments,the pendant hydrophilic group is one or more (e.g., 2, 3, 4, 5, 6, 7, 8,9, 10 or more) amino groups. In some cases, the pendant hydrophilicgroup is one or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10 or more)carboxylate groups. For example, the aliphatic group can includepolyacrylic acid. In some cases, the pendant hydrophilic group is one ormore (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10 or more) sulfonate groups. Insome cases, the pendant hydrophilic group is one or more (e.g., 2, 3, 4,5, 6, 7, 8, 9, 10 or more) phosphate groups. In some embodiments, thependant hydrophilic group is one or more ammonium groups (e.g., tertiaryand/or quaternary ammonium). In other embodiments, the pendanthydrophilic group is one or more zwitterions (e.g., a betaine, such aspoly(carboxybetaine (pCB) and ammonium phosphonates such asphosphatidylcholine).

In some embodiments, the R₂ segment includes charged groups that arecapable of binding to a counterion to ionically crosslink the polymerthe polymer network and form ionomers. In these embodiments, forexample, R₂ is an aliphatic or aromatic group having pendant amino,carboxylate, sulfonate, phosphate, ammonium, zwitterionic groups, orcombinations thereof.

In various cases, the pendant hydrophilic group is at least onepolyether, such as two polyethers. In other cases, the pendanthydrophilic group is at least one polyester. In various cases, thependant hydrophilic group is polylactone (e.g., polyvinylpyrrolidone).Each carbon atom of the pendant hydrophilic group can optionally besubstituted with, e.g., C₁₋₆ alkyl. In some of these embodiments, thealiphatic and aromatic groups can be graft polymers, wherein the pendantgroups are homopolymers (e.g., polyethers, polyesters,polyvinylpyrrolidone).

In some preferred embodiments, the pendant hydrophilic group is apolyether (e.g., polyethylene oxide and polyethylene glycol),polyvinylpyrrolidone, polyacrylic acid, or combinations thereof.

The pendant hydrophilic group can be bonded to the aliphatic group oraromatic group through a linker. The linker can be any bifunctionalsmall molecule (e.g., C₁₋₂₀) capable of linking the pendant hydrophilicgroup to the aliphatic or aromatic group. For example, the linker caninclude a diisocyanate, as previously described herein, which whenlinked to the pendant hydrophilic group and to the aliphatic or aromaticgroup forms a carbamate bond. In some embodiments, the linker can be4,4′-diphenylmethane diisocyanate (MDI), as shown below.

In some exemplary embodiments, the pendant hydrophilic group ispolyethylene oxide and the linking group is MDI, as shown below.

In some cases, the pendant hydrophilic group is functionalized to enableit to bond to the aliphatic or aromatic group, optionally through thelinker. In various embodiments, for example, when the pendanthydrophilic group includes an alkene group, which can undergo a Michaeladdition with a sulfhydryl-containing bifunctional molecule (i.e., amolecule having a second reactive group, such as a hydroxyl group oramino group), to result in a hydrophilic group that can react with thepolymer backbone, optionally through the linker, using the secondreactive group. For example, when the pendant hydrophilic group ispolyvinylpyrrolidone, it can react with the sulfhydryl group onmercaptoethanol to result in hydroxyl-functionalizedpolyvinylpyrrolidone, as shown below.

In some of the embodiments disclosed herein, at least one R₂ segment ispolytetramethylene oxide. In other exemplary embodiments, at least oneR₂ segment can be an aliphatic polyol functionalized with polyethyleneoxide or polyvinylpyrrolidone, such as the polyols described in E.P.Patent No. 2 462 908. For example, the R₂ segment can be derived fromthe reaction product of a polyol (e.g., pentaerythritol or2,2,3-trihydroxypropanol) and either MDI-derivatized methoxypolyethyleneglycol (to obtain compounds as shown in Formulas 6 or 7) or withMDI-derivatized polyvinylpyrrolidone (to obtain compounds as shown inFormulas 8 or 9) that had been previously been reacted withmercaptoethanol, as shown below,

In various cases, at least one R₂ is a polysiloxane. In these cases, R₂can be derived from a silicone monomer of Formula 10, such as a siliconemonomer disclosed in U.S. Pat. No. 5,969,076, which is herebyincorporated by reference:

wherein:

a is 1 to 10 or larger (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10);

each R⁴ independently is hydrogen, C₁₋₁₈ alkyl, C₂₋₁₈ alkenyl, aryl, orpolyether; and

each R⁵ independently is C₁₋₁₀alkylene, polyether, or polyurethane.

In some embodiments, each R⁴ independently is H, C₁₋₁₀ alkyl,C₂₋₁₀alkenyl, C₁₋₆aryl, polyethylene, polypropylene, or polybutylene.For example, each R⁴ can independently be selected from the groupconsisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,s-butyl, t-butyl, ethenyl, propenyl, phenyl, and polyethylene.

In various embodiments, each R⁵ independently is C₁₋₁₀alkylene (e.g.,methylene, ethylene, propylene, butylene, pentylene, hexylene,heptylene, octylene, nonylene, or decylene). In other cases, each R⁵ ispolyether (e.g., polyethylene, polypropylene, or polybutylene). Invarious cases, each R⁵ is polyurethane.

In some embodiments, the hydrogel includes a crosslinked polymericnetwork that includes copolymer chains that are derivatives ofpolyurethane. This crosslinked polymeric network can be produced bypolymerizing one or more isocyanates with one or more polyaminocompounds, polysulfhydryl compounds, or combinations thereof, as shownin Formulas 11 and 12, below:

wherein the variables are as described above. Additionally, theisocyanates can also be chain extended with one or more polyamino orpolythiol chain extenders to bridge two or more isocyanates, such aspreviously described for the polyurethanes of Formula 2.

In some embodiments, the polyurethane hydrogel is composed of MDI, PTMO,and 1,4-butylene glycol, as described in U.S. Pat. No. 4,523,005, whichis hereby incorporated by reference in its entirety.

In some embodiments, the polyurethane hydrogel is physically crosslinkedthrough e.g., nonpolar or polar interactions between the urethane orcarbamate groups on the polymers (the hard segments), and is athermoplastic polyurethane (TPU), or specifically, a hydrophilicthermoplastic polyurethane. In these embodiments, component R₁ inFormula 1, and components R₁ and R₃ in Formula 2, forms the portion ofthe polymer often referred to as the “hard segment”, and component R₂forms the portion of the polymer often referred to as the “softsegment”. In these embodiments, the soft segment can be covalentlybonded to the hard segment.

Commercially available thermoplastic polyurethane hydrogels suitable forthe present use include, but are not limited to those under thetradename “TECOPHILIC”, such as TG-500, TG-2000, SP-80A-150, SP-93A-100,SP-60D-60 (Lubrizol, Countryside, Ill.), “ESTANE” (e.g., ALR G 500;Lubrizol, Countryside, Ill.).

In various embodiments, the polyurethane hydrogel is covalentlycrosslinked, as previously described herein.

In some embodiments, the polyamide segment of the polyamide hydrogelcomprises or consists essentially of a polyamide. The polyamide hydrogelcan be formed from the polycondensation of a polyamide prepolymer with ahydrophilic prepolymer to form a block copolyamide.

In some embodiments, the polyamide segment of the polyamide hydrogel canbe derived from the condensation of polyamide prepolymers, such aslactams, amino acids, and/or diamino compounds with dicarboxylic acids,or activated forms thereof. The resulting polyamide segments includeamide linkages (—(CO)NH—). The term “amino acid” refers to a moleculehaving at least one amino group and at least one carboxyl group. Eachpolyamide segment of the polyamide hydrogel can be the same ordifferent.

In some embodiments, the polyamide segment is derived from thepolycondensation of lactams and/or amino acids, and includes an amidesegment having a structure shown in Formula 13, below, wherein R₆ is thesegment of the block copolymer derived from the lactam or amino acid,and R₂ is the segment derived from a hydrophilic prepolymer:

In some embodiments, R₆ is derived from a lactam. In some cases, R₆ isderived from a C₃₋₂₀ lactam, or a C₄₋₁₅ lactam, or a C₆₋₁₂ lactam. Forexample, R₆ can be derived from caprolactam or laurolactam. In somecases, R₆′ is derived from one or more amino acids. In various cases, R₆is derived from a C₄₋₂₅ amino acid, or a C₅₋₂₀ amino acid, or a C₈₋₁₅amino acid. For example, R₆′ can be derived from 12-aminolauric acid or11-aminoundecanoic acid.

In some cases, Formula 13 includes a polyamide-polyether block copolymersegment, as shown below:

wherein m is 3-20, and n is 1-8. In some exemplary embodiments, m is4-15, or 6-12 (e.g., 6, 7, 8, 9, 10, 11, or 12), and n is 1 2, or 3. Forexample, m can be 11 or 12, and n can be 1 or 3.

In various embodiments, the polyamide segment of the polyamide hydrogelis derived from the condensation of diamino compounds with dicarboxylicacids, or activated forms thereof, and includes an amide segment havinga structure shown in Formula 15, below, wherein R₇ is the segment of theblock copolymer derived from the diamino compound, R₈ is the segmentderived from the dicarboxylic acid compound, and R₂ is the segmentderived from a hydrophilic prepolymer:

In some embodiments, R₇ is derived from a diamino compound that includesan aliphatic group having C₄₋₁₅ carbon atoms, or C₅₋₁₀ carbon atoms, orC₈₋₉ carbon atoms. In some embodiments, the diamino compound includes anaromatic group, such as phenyl, naphthyl, xylyl, and tolyl. Suitablediamino compounds include, but are not limited to, hexamethylene diamine(HMD), tetramethylene diamine, trimethyl hexamethylene diamine (TMD),m-xylylene diamine (MXD), and 1,5-pentamine diamine. In variousembodiments, R₈ is derived from a dicarboxylic acid or activated formthereof, includes an aliphatic group having C₄₋₁₅ carbon atoms, or C₅₋₁₂carbon atoms, or C₈₋₁₀ carbon atoms. In some cases, the dicarboxylicacid or activated form thereof includes an aromatic group, such asphenyl, naphthyl, xylyl, and tolyl. Suitable carboxylic acids oractivated forms thereof include, but are not limited to adipic acid,sebacic acid, terephthalic acid, and isophthalic acid. In someembodiments, the copolymer chains are substantially free of aromaticgroups.

In some preferred embodiments, each polyamide segment is independentlyderived from a polyamide prepolymer selected from the group consistingof 12-aminolauric acid, caprolactam, hexamethylene diamine and adipicacid.

Additionally, the polyamide hydrogels can also be chain extended withone or more polyamino, polycarboxyl (or derivatives thereof), or aminoacid chain extenders, as previously described herein. In someembodiments, the chain extender can include a diol, dithiol, aminoalcohol, aminoalkyl mercaptan, hydroxyalkyl mercaptan, a phosphite or abisacyllactam compound (e.g., triphenylphosphite, N,N′-terephthaloylbis-laurolactam, and diphenyl isophthalate).

Each component R₂ of Formula 13 and 15 independently is polyether,polyester, polycarbonate, an aliphatic group, or an aromatic group,wherein the aliphatic group or aromatic group is substituted with one ormore pendant hydrophilic groups, as previously described herein, whereinthe pendant group can optionally be bonded to the aliphatic or aromaticgroup through a linker, as previously described herein.

In some preferred embodiments, R₂ is derived from a compound selectedfrom the group consisting of polyethylene oxide (PEO), polypropyleneoxide (PPO), polytetrahydrofuran (PTHF), polytetramethylene oxide(PTMO), a polyethylene oxide-functionalized aliphatic or aromatic group,a polyvinylpyrrolidone-functionalized aliphatic of aromatic group, andcombinations thereof. In various cases, R₂ is derived from a compoundselected from the group consisting of polyethylene oxide (PEO),polypropylene oxide (PPO), polytetramethylene oxide (PTMO), apolyethylene oxide-functionalized aliphatic or aromatic group, andcombinations thereof. For example, R₂ can be derived from a compoundselected from the group consisting of polyethylene oxide (PEO),polytetramethylene oxide (PTMO), and combinations thereof.

In some embodiments, the polyamide hydrogel is physically crosslinkedthrough, e.g., nonpolar or polar interactions between the polyamidegroups on the polymers, and is a thermoplastic polyamide, or inparticular, a hydrophilic thermoplastic polyamide. In these embodiments,component R₆ in Formula 13 and components R₇ and R₈ in Formula 15 formthe portion of the polymer often referred to as the “hard segment”, andcomponent R₂ forms the portion of the polymer often referred to as the“soft segment”. Therefore, in some embodiments, the hydrogel orcrosslinked polymeric network can include a physically crosslinkedpolymeric network having one or more polymer chains with amide linkages.

In some embodiments, the hydrogel or crosslinked polymeric networkincludes plurality of block copolymer chains, wherein at least a portionof the block copolymer chains each include a polyamide block and ahydrophilic block, (e.g., a polyether block) covalently bonded to thepolyamide block to result in a thermoplastic polyamide block copolymerhydrogel (i.e., a polyamide-polyether block copolymer). In theseembodiments, the polyamide segments can interact with each other to formthe crystalline region. Therefore, the polyamide block copolymer chainscan each comprise a plurality of polyamide segments forming crystallineregions with other polyamide segments of the polyamide block copolymerchains, and a plurality of hydrophilic segments covalently bonded to thepolyamide segments.

In some embodiments, the polyamide is polyamide-11 or polyamide-12 andthe polyether is selected from the group consisting of polyethyleneoxide, polypropylene oxide, and polytetramethylene oxide. Commerciallyavailable thermoplastic polyamide hydrogels suitable for the present useinclude those under the tradename “PEBAX” (e.g., “PEBAX MH1657” and“PEBAX MV1074”) from Arkema, Inc., Clear Lake, Tex.), and “SERENE”coating (Sumedics, Eden Prairie, Minn.).

In various embodiments, the polyamide hydrogel is covalentlycrosslinked, as previously described herein.

In some embodiments, the hydrogel comprises or consists essentially of apolyolefin hydrogel. The polyolefin hydrogel can be formed through freeradical, cationic, and/or anionic polymerization by methods well knownto those skilled in the art (e.g., using a peroxide initiator, heat,and/or light).

In some embodiments, the hydrogel or crosslinked polymeric network caninclude one or more, or a plurality, of polyolefin chains. For instance,the polyolefin can include polyacrylamide, polyacrylate, polyacrylicacid and derivatives or salts thereof, polyacrylohalide,polyacrylonitrile, polyallyl alcohol, polyallyl ether, polyallyl ester,polyallyl carbonate, polyallyl carbamate, polyallyl sulfone, polyallylsulfonic acid, polyallyl amine, polyallyl cyanide, polyvinyl ester,polyvinyl thioester, polyvinyl pyrrolidone, polyα-olefin, polystyrene,and combinations thereof. Therefore, the polyolefin can be derived froma monomer selected from the group consisting of acrylamide, acrylate,acrylic acid and derivatives or salts thereof, acrylohalide,acrylonitrile, allyl alcohol, allyl ether, allyl ester, allyl carbonate,allyl carbamate, allyl sulfone, allyl sulfonic acid, allyl amine, allylcyanide, vinyl ester, vinyl thioester, vinyl pyrrolidone, α-olefin,styrene, and combinations thereof.

In some embodiments, the polyolefin is derived from an acrylamide.Suitable acrylamides can include, but are not limited to, acrylamide,methacrylamide, ethylacrylamide, N, N-dimethylacrylamide,N-isopropylacrylamide, N-tert-butylacrylamide,N-isopropylmethacrylamide, N-phenylacrylamide,N-diphenylmethylacrylamide, N-(triphenylmethyl)methacrylamide,N-hydroxyethyl acrylamide, 3-acryloylamino-1-propanol,N-acryloylamido-ethoxyethanol, N-[tris(hydroxymethyl)methyl]acrylamide,N-(3-methoxypropyl)acrylamide,N-[3-(dimethylamino)propyl]methacrylamide,(3-acrylamidopropyl)trimethylammonium chloride, diacetone acrylamide,2-acrylamido-2-methyl-1-propanesulfonic acid, salts of2-acrylamido-2-methyl-1-propanesulfonic acid, 4-acryloylmorpholine, andcombinations thereof. For example, the acrylamide prepolymer can beacrylamide or methacrylamide.

In some cases, the polyolefin is derived from an acrylate (e.g.,acrylate and/or alkylacrylate). Suitable acrylates include, but are notlimited to, methyl acrylate, ethyl acrylate, propyl acrylate, isopropylacrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate,hexyl acrylate, isooctyl acrylate, isodecyl acrylate, octadecylacrylate, lauryl acrylate, 2-ethylhexyl acrylate, 4-tert-butylcyclohexylacrylate, 3,5,5-trimethylhexyl acrylate, isobornyl acrylate, vinylmethacrylate, allyl methacrylate, methyl methacrylate, ethylmethacrylate, butyl methacrylate, isobutyl methacrylate, tert-butylmethacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isodecylmethacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexylmethacrylate, 3,3,5-trimethylcyclohexyl methacrylate, combinationsthereof, and the like. For example, acrylate prepolymer can be methylacrylate, ethyl methacrylate, or 2-hydroxyethyl methacrylate.

In some cases, the polyolefin is derived from an acrylic acid or aderivative or salt thereof. Suitable acrylic acids, but are not limitedto acrylic acid, sodium acrylate, methacrylic acid, sodium methacrylate,2-ethylacrylic acid, 2-propylacrylic acid, 2-bromoacrylic acid,2-(bromomethyl)acrylic acid, 2-(trifluoromethyl)acrylic acid, acryloylchloride, methacryloyl chloride, and 2-ethylacryloyl chloride.

In various embodiments, the polyolefin can be derived from an allylalcohol, allyl ether, allyl ester, allyl carbonate, allyl carbamate,allyl sulfone, allyl sulfonic acid, allyl amine, allyl cyanide, or acombination thereof. For example, the polyolefin segment can be derivedfrom allyloxyethanol, 3-allyloxy-1,2-propanediol, allyl butyl ether,allyl benzyl ether, allyl ethyl ether, allyl phenyl ether, allyl2,4,6-tribromophenyl ether, 2-allyloxybenzaldehyde,2-allyloxy-2-hydroxybenzophenone, allyl acetate, allyl acetoacetate,allyl chloroacetate, allylcyanoacetate, allyl2-bromo-2-methylpropionate, allyl butyrate, allyltrifluoroacetae, allylmethyl carbonate, tert-butyl N-allylcarbamate, allyl methyl sulfone,3-allyloxy-2-hydroxy-1-propanesulfonic acid,3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt, allylamine, anallylamine salt, and allyl cyanide.

In some cases, the polyolefin can be derived from a vinyl ester, vinylthioester, vinyl pyrrolidone (e.g., N-vinyl pyrrolidone), andcombinations thereof. For example, the vinyl monomer can be vinylchloroformate, vinyl acetate, vinyl decanoate, vinyl neodecanoate, vinylneononanoate, vinylpivalate, vinyl propionate, vinyl stearate, vinylvalerate, vinyl trifluoroacetate, vinyl benzoate, vinyl4-tert-butylbenzoate, vinyl cinnamate, butyl vinyl ether, tert-butylvinyl ether, cyclohexyl vinyl ether, dodecyl vinyl ether, ethyleneglycol vinyl ether, 2-ethylhexyl vinyl ether, ethyl vinyl ether,ethyl-1-propenyl ether, isobutyl vinyl ether, propyl vinyl ether,2-chloroethyl vinyl ether, 1,4-butanediol vinyl ether,1,4-cyclohexanedimethanol vinyl ether, di(ethylene glycol) vinyl ether,diethyl vinyl orthoformate, vinyl sulfide, vinyl halide, and vinylchloride.

In some embodiments, the polyolefin can be derived from an alpha-olefin,such as 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene,1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-pentadecene,1-heptadecene, and 1-octadecene.

In various cases, the polyolefin segment containing R₇ can be derivedfrom a styrene. Suitable styrene monomers include styrene,α-bromostyrene, 2,4-diphenyl-4-methyl-1-pentene, α-methylstyrene,4-acetoxystyrene, 4-benzhydrylstyrene, 4-tert-butylstyrene,2,4-dimethylstyrene, 2,5-dimethylstyrene, 2-methylstyrene,3-methylstyrene, 4-methylstyrene, 2-(trifluoromethyl)styrene,3-(trifluoromethyl)styrene, 4-(trifluoromethyl)styrene,2,4,6-trimethylstyrene, vinylbenzyl chloride,4-benzyloxy-3-methoxystyrene, 4-tert-butoxystyrene, 3,4-dimethoxystyrene, 4-ethoxystyrene, 4-vinylanisole, 2-bromostyrene,3-bromostyrene, 4-bromosytrene, 4-chloro-α-methylstyrene,2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,6-dichlorostyrene,2,6-difluorostyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene,2,3,4,5,6-pentafluorostyrene, N, N-dimethylvinylbenzylamine,2-isopropenylaniline, 4-[N-(methylaminoethyl)aminomethyl]styrene,3-vinylaniline, 4-vinylaniline, (vinylbenzyl)trimethylammonium chloride,4-(diphenylphosphino)styrene, 3-isopropenyl-α,α-dimethylbenzylisocyanate, 3-nitrostyrene, 9-vinylanthracene, 2-vinylnaphthalene,4-vinyl benzocyclobutene, 4-vinylbiphenyl, and vinylbenzoic acid.

In some embodiments, the polyolefin comprises a hydrophilic portion. Thehydrophilic portion of the polyolefin hydrogel can be pendant to thepolyolefin backbone, or the hydrophilic portion can function as acovalent crosslinker of the polyolefin hydrogel. In some embodiments,the hydrophilic portion of the polyolefin hydrogel includes a pendantpolyether, polyester, polycarbonate, hydroxyl, lactone (e.g.,pyrrolidone), amino, carboxylate, sulfonate, phosphate, ammonium (e.g.,tertiary and quaternary ammonium), zwitterion group (e.g., a betaine,such as poly(carboxybetaine (pCB) and ammonium phosphonates such asphosphatidylcholine), or combinations thereof. Polyolefin hydrogelscontaining a pendant hydrophilic portion can be formed by copolymerizinga polyolefin monomer, as previously described, with a second polymerolefin monomer having a hydrophilic side chain, such as acrylic acid orpolyvinylpyrrolidone).

In some embodiments, the polyolefin hydrogel or crosslinked polymericnetwork includes a plurality of polyolefin chains wherein at least aportion of the polyolefin chains each comprise a first chain segmentphysically crosslinked to at least one other polyolefin chain of theplurality of polyolefin chains and one or more hydrophilic chainsegments covalently bonded to the first chain segment.

In other embodiments, the hydrophilic portion of the polyolefin hydrogelis a hydrophilic crosslinker. The crosslinker can include polyether,polyester, polycarbonate, hydroxyl, lactone (e.g., pyrrolidone), amino,carboxylate, sulfonate, phosphate, ammonium (e.g., tertiary andquaternary ammonium), a zwitterion (e.g., a betaine, such aspoly(carboxybetaine (pCB) and ammonium phosphonates such asphosphatidylcholine), and combinations thereof. The hydrophiliccrosslinker can be derived from a molecule having at least twoethylenically-unsaturated groups, such as a polyethylene glycoldimethacrylate.

Suitable commercially available polyolefin films include, but are notlimited to the “POLYOX” product line by Dow Chemical, Midland Mich., andstyrenic block co-polymers. Examples of styrenic co-polymers include,but are not limited to TPE-s (e.g., styrene-butadiene-styrene (SBS)block copolymers, such as “SOFPRENE” andstyrene-ethylene-butylene-styrene (SEBS) block copolymer, such as“LAPRENE”, by SO.F.TER. GROUP, Lebanon, Tenn.); thermoplasticcopolyester elastomers (e.g., thermoplastic elastomer vulconates (TPE-vor TPV)), such as “FORPRENE” by SO.F.TER. GROUP), “TERMOTON-V” byTermopol, Istanbul Turkey; and TPE block copolymers, such as“SANTOPRENE” (ExxonMobil, Irving, Tex.).

In some embodiments, the polyolefin prepolymer described above isco-polymerized with a silicone prepolymer to form a silicone hydrogel.In these embodiments, the silicone prepolymer, the polyolefinprepolymer, or both can function as the crosslinker.

Examples of silicone monomers include, but are not limited to,3-methacryloxypropyl tris(trimethylsiloxy)silane (TRIS), andmonomethacryloxypropyl terminated polydimethylsiloxane (mPDMS), mvinyl[3-[3,3,3-trimethyl-1,1bis(trimethylsiloxy)-disiloxanyl]propyl]carbamate,3-methacryloxypropyl-bis(trimethylsiloxy)methyl silane, andmethacryloxypropylpentamethyl disiloxane.

As discussed above, the film material can also optionally include one ormore additives, such as antioxidants, colorants, stabilizers,anti-static agents, wax packages, antiblocking agents, crystalnucleating agents, melt strength enhancers, anti-stain agents, stainblockers, hydrophilicity-enhancing additives, and combinations thereof.

Examples of particularly suitable additives includehydrophilicity-enhancing additives, such as one or more super-absorbentpolymers (e.g., superabsorbent polyacrylic acid or copolymers thereof).Examples of hydrophilicity-enhancing additives include thosecommercially available under the tradenames “CREASORB” or “CREABLOCK” byEvonik, Mobile, Ala., “HYSORB” by BASF, Wyandotte, Mich., “WASTE LOCKPAM” by M² Polymer Technologies, Inc., Dundee Township, Ill., and “AQUAKEEP” by Sumitomo Seika, New York, N.Y. The incorporation of thehydrophilicity-enhancing additive can assist the hydrogel by increasingthe water uptake rate and/or capacity for the film material. Examples ofsuitable concentrations of the hydrophilicity-enhancing additive in thefilm material range from 0.1% to 15% by weight, from 0.5% to 10% byweight, or from 1% to 5% by weight, based on the total weight of thefilm material.

In some aspects, the outsole film can define an exterior orground-facing surface of the outsole. Alternatively, a water-permeablemembrane can define the exterior or ground-facing surface of theoutsole, and can be in direct contact with the outsole film. Forexample, at least a portion of the exterior surface of the outsole canbe defined by a first side of the water-permeable membrane, with theoutsole film present between the backing plate/outsole substrate and themembrane.

The level of water permeability of the water-permeable membrane ispreferably sufficient for water to rapidly partition from the exteriorsurface of the outsole (i.e., the first side of the membrane), acrossthe second side of the membrane, and into the outsole film. For example,the level of water permeability of the water-permeable membrane can besufficient for a sample of the outsole obtained in accordance with theFootwear Sampling Procedure to have a water uptake capacity of greaterthan 40% by weight at 24 hours and/or at 1 hour.

The articles of footwear of the present disclosure can be manufacturedusing a variety of different footwear manufacturing techniques. Forexample, the outsole film (e.g., the film 116) and the backing plate orsubstrate can be formed using methods such as injection molding, castmolding, thermoforming, vacuum forming, extrusion, spray coating, andthe like.

In a first embodiment, the outsole is formed with the use of aco-extruded outsole plate. In this case, the film material can beco-extruded with a thermoplastic material used to form a thin backingsubstrate, where the resulting co-extrudate can be provided in a web orsheet form. The web or sheet can then be placed in a vacuumthermoforming tool to produce the three-dimensional geometry of theoutsole ground-facing side (referred to as an outsole face precursor).The backing substrate provides a first function in this step by creatinga structural support for the relatively thinner and weaker outsole film.The outsole face precursor can then be trimmed to form its perimeter andorifices to receive traction elements, thereby providing an outsoleface.

The outsole face can then be placed in a mold cavity, where the outsolefilm is preferably positioned away from the injection sprues. Anotherthermoplastic material can then be back injected into the mold to bondto the backing substrate, opposite of the outsole film. This illustratesthe second function of the backing substrate, namely to protect theoutsole film from the injection pressure. The injected thermoplasticmaterial can be the same or different from the material used to producethe backing substrate. Preferably, they include the same or similarmaterials (e.g., both being thermoplastic polyurethanes). As such, thebacking substrate and the injected material in the mold form the outsolebacking plate, which is secured to the outsole film (during theco-extrusion step).

In a second embodiment, the outsole is formed with the use of injectionmolding. In this case, a substrate material is preferably injected intoa mold to produce the outsole backing plate. The outsole backing platecan then be back injected with the film material to produce the outsolefilm bonded to the outsole backing plate.

In either embodiment, after the outsole is manufactured, it can bedirectly or indirectly secured to a footwear upper to provide thearticle of footwear of the present disclosure. In particular, outsolefilm can function as a ground-facing surface of the outsole, which ispositioned on the opposite side of the outsole backing plate from theupper.

Property Analysis and Characterization Procedure

Various properties can be determined for outsole films of footwearaccording to the following methodologies.

1. Sampling Procedures

As mentioned above, it has been found that when the outsole film issecured to another substrate, the interfacial bond can restrict theextent that the outsole film can take up water and/or swell. As such,various properties of the outsole film can be characterized usingsamples prepared with the following sampling procedures:

A. Footwear Sampling Procedure

This procedure can be used to obtain a sample of the outsole film whenthe outsole film is a component of a footwear outsole or article offootwear (e.g., bonded to an outsole substrate, such as an outsolebacking plate). An outsole sample including the outsole film in anon-wetted state (e.g., at 25° C. and 20% relative humidity) is cut fromthe article of footwear using a blade. This process is performed byseparating the outsole from an associated footwear upper, and removingany materials from the outsole top surface (e.g., corresponding to thetop surface 142) that can uptake water and potentially skew the wateruptake measurements of the outsole film. For example, the outsole topsurface can be skinned, abraded, scraped, or otherwise cleaned to removeany upper adhesives, yarns, fibers, foams, and the like that couldpotentially take up water themselves.

The resulting sample includes the outsole film and any outsole substratebonded to the outsole film, and maintains the interfacial bond betweenthe outsole film and the associated outsole substrate. As such, thistest can simulate how the outsole film will perform as part of anarticle of footwear. Additionally, this sample is also useful in caseswhere the interfacial bond between the outsole film and the outsolesubstrate is less defined, such as where the material of the outsolefilm is highly diffused into the material of the outsole substrate(e.g., with a concentration gradient).

The sample is taken at a location along the outsole that provides asubstantially constant film thickness for the outsole film (within+/−10% of the average film thickness), such as in a forefoot region,midfoot region, or a heel region of the outsole, and has a surface areaof 4 square centimeters (cm²). In cases where the outsole film is notpresent on the outsole in any segment having a 4 cm² surface area and/orwhere the film thickness is not substantially constant for a segmenthaving a 4 cm² surface area, sample sizes with smaller cross-sectionalsurface areas can be taken and the area-specific measurements areadjusted accordingly.

B. Co-Extruded Film Sampling Procedure

This procedure can be used to obtain a sample of an outsole film whenthe outsole film is co-extruded onto a backing substrate. The backingsubstrate is produced from a material that is compatible with thematerial of the outsole film, such as a material used to form an outsolebacking plate for the outsole film.

It has been found that samples taken from co-extruded outsole films aresuitable substitutes to samples taken from articles of footwear.Additionally, this sample is also useful in cases where the interfacialbond between the outsole film and the backing substrate is less defined,such as where the material of the outsole film is highly diffused intothe material of the backing substrate (e.g., with a concentrationgradient).

In this case, the outsole film is co-extruded with the backing substrateas a web or sheet having a substantially constant film thickness for theoutsole film (within +/−10% of the average film thickness), and cooledto solidify the resulting web or sheet. A sample of the outsole-filmsecured to the backing substrate is then cut from the resulting web orsheet, with a sample size surface area of 4 cm², such that the outsolefilm of the resulting sample remains secured to the backing substrate.

C. Neat Film Sampling Procedure

This procedure can be used to obtain a sample of an outsole film whenthe outsole film is isolated in a neat form (i.e., without any bondedsubstrate). In this case, the outsole film is extruded as a web or sheethaving a substantially constant film thickness for the outsole film(within +/−10% of the average film thickness), and cooled to solidifythe resulting web or sheet. A sample of the outsole film having asurface area of 4 cm² is then cut from the resulting web or sheet.

Alternatively, if a source of the outsole film material is not availablein a neat form, the outsole film can be cut from an outsole substrate ofa footwear outsole, or from a backing substrate of a co-extruded sheetor web, thereby isolating the outsole film. In either case, a sample ofthe outsole film having a surface area of 4 cm² is then cut from theresulting isolated film.

D. Neat Material Sampling Procedure

This procedure can be used to obtain a sample of a material used to formthe outsole film. In this case, the outsole film material is provided inmedia form, such as flakes, granules, powders, pellets, and the like. Ifa source of the outsole film material is not available in a neat form,the outsole film can be cut, scraped, or ground from an outsolesubstrate of a footwear outsole or from a backing substrate of aco-extruded sheet or web, thereby isolating the outsole film material.

2. Water Uptake Capacity Test

This test measures the water uptake capacity of the outsole film after agiven soaking duration for a sample (e.g., taken with theabove-discussed Footwear Sampling Procedure, Co-extruded Film SamplingProcedure, or the Neat Film Sampling Procedure). The sample is initiallydried at 60° C. until there is no weight change for consecutivemeasurement intervals of at least 30 minutes apart (e.g., a 24-hourdrying period at 60° C. is typically a suitable duration). The totalweight of the dried sample (Wt,_(sample,dry)) is then measured in grams.The dried sample is then allowed to cool down to 25° C., and is fullyimmersed in a deionized water bath maintained at 25° C. After a givensoaking duration, the sample is removed from the deionized water bath,blotted with a cloth to remove surface water, and the total weight ofthe soaked sample (Wt,_(sample,wet)) is measured in grams.

Any suitable soaking duration can be used, where a 24-hour soakingduration is believed to simulate saturation conditions for the outsolefilms of the present disclosure (i.e., the outsole film will be in itssaturated state). Accordingly, as used herein, the expression “having awater uptake capacity at 5 minutes of . . . ” refers to a soakingduration of 5 minutes, having a water uptake capacity at 1 hour of . . .” refers to a soaking duration of 1 hour, the expression “having a wateruptake capacity at 24 hours of . . . ” refers to a soaking duration of24 hours, and the like.

As can be appreciated, the total weight of a sample taken pursuant tothe Footwear Sampling Procedure or the Co-extruded Film SamplingProcedure includes the weight of the outsole film as dried or soaked(Wt,_(film,dry) or Wt,_(film,wet)) and the weight of the outsole orbacking substrate (Wt,_(substrate)). In order to determine a change inweight of the outsole film due to water uptake, the weight of thesubstrate (Wt,_(substrate)) needs to be subtracted from the samplemeasurements.

The weight of the substrate (Wt,_(substrate)) is calculated using thesample surface area (e.g., 4 cm²), an average measured thickness of thesubstrate in the sample, and the average density of the substratematerial. Alternatively, if the density of the material for thesubstrate is not known or obtainable, the weight of the substrate(Wt,_(substrate)) is determined by taking a second sample using the samesampling procedure as used for the primary sample, and having the samedimensions (surface area and film/substrate thicknesses) as the primarysample. The outsole film of the second sample is then cut apart from thesubstrate of the second sample with a blade to provide an isolatedsubstrate. The isolated substrate is then dried at 60° C. for 24 hours,which can be performed at the same time as the primary sample drying.The weight of the isolated substrate (Wt,_(substrate)) is then measuredin grams.

The resulting substrate weight (Wt,_(substrate)) is then subtracted fromthe weights of the dried and soaked primary sample (Wt,_(sample,dry) andWt,_(sample,wet)) to provide the weights of the outsole film as driedand soaked (Wt,_(film,dry) and Wt,_(film, wet)), as depicted below byEquations 1 and 2:Wt, _(film,dry) =Wt, _(sample,dry) −Wt, _(substrate)  (Equation 1)Wt, _(film,wet) =Wt, _(sample,wet) −Wt, _(substrate)  (Equation 2)

For outsole film samples taken pursuant to the Neat Film SamplingProcedure, the substrate weight (Wt,_(substrate)) is zero. As such,Equation 1 collapses to Wt,_(film,dry)=Wt,_(sample,dry) and Equation 2collapses to Wt,_(film,wet)=Wt,_(sample,wet).

The weight of the dried outsole film (Wt,_(film,dry)) is then subtractedfrom the weight of the soaked outsole film (Wt,_(film,wet)) to providethe weight of water that was taken up by the outsole film, which is thendivided by the weight of the dried outsole film (Wt,_(film,dry)) toprovide the water uptake capacity for the given soaking duration as apercentage, as depicted below by Equation 3:Water Uptake Capacity=(Wt, _(film,wet) −Wt, _(film,dry))/(Wt,_(film,dry))×100%  (Equation 3)For example, a water uptake capacity of 50% at 1 hour means that thesoaked outsole film weighed 1.5 times more than its dry-state weightafter soaking for 1 hour, where there is a 1:2 weight ratio of water tooutsole film material. Similarly, a water uptake capacity of 500% at 24hours means that the soaked outsole film weighed 5 times more than itsdry-state weight after soaking for 24 hours, where there is a 4:1 weightratio of water to outsole film material.3. Water Uptake Rate Test

This test measures the water uptake rate of the outsole film by modelingweight gain as a function of soaking time for a sample with aone-dimensional diffusion model. The sample can be taken with any of theabove-discussed Footwear Sampling Procedure, Co-extruded Film SamplingProcedure, or the Neat Film Sampling Procedure. The sample is initiallydried at 60° C. until there is no weight change for consecutivemeasurement intervals of at least 30 minutes apart (a 24-hour dryingperiod at 60° C. is typically a suitable duration). The total weight ofthe dried sample (Wt,_(sample,dry)) is then measured in grams.Additionally, the average thickness of the outsole film for the driedsample is measured for use in calculating the water uptake rate, asexplained below.

The dried sample is then allowed to cooled down to 25° C., and is fullyimmersed in a deionized water bath maintained at 25° C. Between soakingdurations of 1, 2, 4, 9, 16, and 25 minutes, the sample is removed fromthe deionized water bath, blotted with a cloth to remove surface water,and the total weight of the soaked sample t (Wt,_(sample,wet,t)) ismeasured, where “t” refers to the particular soaking-duration data point(e.g., 1, 2, 4, 9, 16, or 25 minutes).

The exposed surface area of the soaked sample (A_(t)) is also measuredwith calipers for determining the specific weight gain, as explainedbelow. The exposed surface area refers to the surface area that comesinto contact with the deionized water when fully immersed in the bath.For samples obtained using the Footwear Sampling Procedure and theCo-extruded Film Sampling Procedure, the samples only have one majorsurface exposed. However, for samples obtained using the Neat FilmSampling Procedure, both major surfaces are exposed. For convenience,the surface areas of the peripheral edges of the sample are ignored dueto their relatively small dimensions.

The measured sample is fully immersed back in the deionized water bathbetween measurements. The 1, 2, 4, 9, 16, and 25 minute durations referto cumulative soaking durations while the sample is fully immersed inthe deionized water bath (i.e., after the first minute of soaking andfirst measurement, the sample is returned to the bath for one moreminute of soaking before measuring at the 2-minute mark).

As discussed above in the Water Uptake Capacity Test, the total weightof a sample taken pursuant to the Footwear Sampling Procedure or theCo-extruded Film Sampling Procedure includes the weight of the outsolefilm as dried or soaked (Wt,_(film,dry) or Wt,_(film,wet,t)) and theweight of the outsole or backing substrate (Wt,_(substrate)). In orderto determine a weight change of the outsole film due to water uptake,the weight of the substrate (Wt,_(substrate)) needs to be subtractedfrom the sample weight measurements. This can be accomplished using thesame steps discussed above in the Water Uptake Capacity Test to providethe resulting outsole film weights Wt,_(film,dry) and Wt,_(film,wet,t)for each soaking-duration measurement.

The specific weight gain (Ws,_(film,t)) from water uptake for eachsoaked sample is then calculated as the difference between the weight ofthe soaked sample (Wt,_(film,wet,t)) and the weight of the initial driedsample (Wt,_(film,dry)), where the resulting difference is then dividedby the exposed surface area of the soaked sample (A_(t)), as depictedbelow by Equation 4:Ws, _(film,t)=(Wt, _(film,wet,t) −Wt, _(film,dry))/A _(t)  (Equation 4)where t refers to the particular soaking-duration data point (e.g., 1,2, 4, 9, 16, or 25 minutes), as mentioned above.

The water uptake rate for the outsole film is then determined as theslope of the specific weight gains (Ws,_(film,t)) versus the square rootof time (in minutes), as determined by a least squares linear regressionof the data points. For the outsole films of the present disclosure, theplot of the specific weight gains (Ws,_(film,t)) versus the square rootof time (in minutes) provides an initial slope that is substantiallylinear (to provide the water uptake rate by the linear regressionanalysis). However, after a period of time depending on the thickness ofthe outsole film, the specific weight gains will slow down, indicating areduction in the water uptake rate, until the saturated state isreached. This is believed to be due to the water being sufficientlydiffused throughout the outsole film as the water uptake approachessaturation, and will vary depending on film thickness.

As such, for the outsole film having an average dried film thickness (asmeasured above) less than 0.3 millimeters, only the specific weight gaindata points at 1, 2, 4, and 9 minutes are used in the linear regressionanalysis. In these cases, the data points at 16 and 25 minutes can beginto significantly diverge from the linear slope due to the water uptakeapproaching saturation, and are omitted from the linear regressionanalysis. In comparison, for the outsole film having an average driedfilm thickness (as measured above) of 0.3 millimeters or more, thespecific weight gain data points at 1, 2, 4, 9, 16, and 25 minutes areused in the linear regression analysis. The resulting slope defining thewater uptake rate for the sampled outsole film has units ofweight/(surface area-square root of time), such asgrams/(meter²-minutes^(1/2)).

Furthermore, some film or substrate surfaces can create surfacephenomenon that quickly attract and retain water molecules (e.g., viasurface hydrogen bonding or capillary action) without actually drawingthe water molecules into the film or substrate. Thus, samples of thesefilms or substrates can show rapid specific weight gains for the1-minute sample, and possibly for the 2-minute sample. After that,however, further weight gain is negligible. As such, the linearregression analysis is only applied if the specific weight gain datapoints at 1, 2, and 4 minutes continue to show an increase in wateruptake. If not, the water uptake rate under this test methodology isconsidered to be about zero grams/(meter²-minutes^(1/2)).

4. Swelling Capacity Test

This test measures the swelling capacity of the outsole film in terms ofincreases in film thickness and film volume after a given soakingduration for a sample (e.g., taken with the above-discussed FootwearSampling Procedure, Co-extruded Film Sampling Procedure, or the NeatFilm Sampling Procedure). The sample is initially dried at 60° C. untilthere is no weight change for consecutive measurement intervals of atleast 30 minutes apart (a 24-hour drying period is typically a suitableduration). The film dimensions of the dried sample are then measured(e.g., thickness, length, and width for a rectangular sample; thicknessand diameter for a circular sample, etc. . . . ). The dried sample isthen fully immersed in a deionized water bath maintained at 25° C. Aftera given soaking duration, the sample is removed from the deionized waterbath, blotted with a cloth to remove surface water, and the same filmdimensions for the soaked sample are re-measured.

Any suitable soaking duration can be used. Accordingly, as used herein,the expressions “having a swelling thickness (or volume) increase at 5minutes of . . . ” refers to a soaking duration of 5 minutes, having aswelling thickness (or volume) increase at 1 hour of . . . ” refers to atest duration of 1 hour, the expression “having a swelling thickness (orvolume) increase at 24 hours of . . . ” refers to a test duration of 24hours, and the like.

The swelling of the outsole film is determined by (i) an increase in thefilm thickness between the dried and soaked outsole film, by (ii) anincrease in the film volume between the dried and soaked outsole film,or (iii) both. The increase in film thickness between the dried andsoaked film is calculated by subtracting the measured film thickness ofthe initial dried film from the measured film thickness of the soakedfilm. Similarly, the increase in film volume between the dried andsoaked film is calculated by subtracting the measured film volume of theinitial dried film from the measured film volume of the soaked film. Theincreases in the film thickness and volume can also be represented aspercentage increases relative to the dry-film thickness or volume,respectively.

5. Contact Angle Test

This test measures the contact angle of the outsole film surface (or ofthe outsole surface) based on a static sessile drop contact anglemeasurement for a sample (e.g., taken with the above-discussed FootwearSampling Procedure, Co-extruded Film Sampling Procedure, or the NeatFilm Sampling Procedure). The contact angle refers to the angle at whicha liquid interface meets a solid surface, and is an indicator of howhydrophilic the surface is.

For a dry test (i.e., to determine a dry-state contact angle), thesample is initially equilibrated at 25° C. and 20% humidity for 24hours. For a wet test (i.e., to determine a wet-state contact angle),the sample is fully immersed in a deionized water bath maintained at 25°C. for 24 hours. After that, the sample is removed from the bath andblotted with a cloth to remove surface water, and clipped to a glassslide if needed to prevent curling.

The dry or wet sample is then placed on a moveable stage of a contactangle goniometer commercially available under the tradename “RAME-HARTF290” from Rame-Hart Instrument Co., Succasunna, N.J. A 10-microliterdroplet of deionized water is then placed on the sample using a syringeand automated pump. An image is then immediately taken of the droplet(before film can take up the droplet), and the contact angle of bothedges of the water droplet are measured from the image. The decrease incontact angle between the dried and wet samples is calculated bysubtracting the measured contact angle of the wet film from the measuredcontact angle of the dry film.

6. Coefficient of Friction Test

This test measures the coefficient of friction of the outsole filmsurface (or of the outsole surface) for a sample (e.g., taken with theabove-discussed Footwear Sampling Procedure, Co-extruded Film SamplingProcedure, or the Neat Film Sampling Procedure). For a dry test (i.e.,to determine a dry-state coefficient of friction), the sample isinitially equilibrated at 25° C. and 20% humidity for 24 hours. For awet test (i.e., to determine a wet-state coefficient of friction), thesample is fully immersed in a deionized water bath maintained at 25° C.for 24 hours. After that, the sample is removed from the bath andblotted with a cloth to remove surface water.

The measurement is performed with an aluminum sled mounted on analuminum test track, which is used to perform a sliding friction testfor test sample on an aluminum surface of the test track. The test trackmeasures 127 millimeters wide by 610 millimeters long. The aluminum sledmeasures 76.2 millimeters×76.2 millimeters, with a 9.5 millimeter radiuscut into the leading edge. The contact area of the aluminum sled withthe track is 76.2 millimeters×66.6 millimeters, or 5,100 squaremillimeters).

The dry or wet sample is attached to the bottom of the sled using a roomtemperature-curing two-part epoxy adhesive commercially available underthe tradename “LOCTITE 608” from Henkel, Düsseldorf, Germany. Theadhesive is used to maintain the planarity of the wet sample, which cancurl when saturated. A polystyrene foam having a thickness of about 25.4millimeters is attached to the top surface of the sled (opposite of thetest sample) for structural support.

The sliding friction test is conducted using a screw-driven load frame.A tow cable is attached to the sled with a mount supported in thepolystyrene foam structural support, and is wrapped around a pulley todrag the sled across the aluminum test track. The sliding or frictionalforce is measured using a load transducer with a capacity of 2,000Newtons. The normal force is controlled by placing weights on top of thealuminum sled, supported by the polystyrene foam structural support, fora total sled weight of 20.9 kilograms (205 Newtons). The crosshead ofthe test frame is increased at a rate of 5 millimeters/second, and thetotal test displacement is 250 millimeters. The coefficient of frictionis calculated based on the steady-state force parallel to the directionof movement required to pull the sled at constant velocity. Thecoefficient of friction itself is found by dividing the steady-statepull force by the applied normal force. Any transient value relatingstatic coefficient of friction at the start of the test is ignored.

7. Storage Modulus Test

This test measures the resistance of the outsole film to being deformed(ratio of stress to strain) when a vibratory or oscillating force isapplied to it, and is a good indicator of film compliance in the dry andwet states. For this test, a sample is provided in neat form using theNeat Film Sampling Procedure, which is modified such that the surfacearea of the test sample is rectangular with dimensions of 5.35millimeters wide and 10 millimeters long. The film thickness can rangefrom 0.1 millimeters to 2 millimeters, and the specific range is notparticularly limited as the end modulus result is normalized accordingto film thickness.

The storage modulus (E′) with units of megaPascals (MPa) of the sampleis determined by dynamic mechanical analysis (DMA) using a DMA analyzercommercially available under the tradename “Q800 DMA ANALYZER” from TAInstruments, New Castle, Del., which is equipped with a relativehumidity accessory to maintain the sample at constant temperature andrelative humidity during the analysis.

Initially, the thickness of the test sample is measured using calipers(for use in the modulus calculations). The test sample is then clampedinto the DMA analyzer, which is operated at the following stress/strainconditions during the analysis: isothermal temperature of 25° C.,frequency of 1 Hertz, strain amplitude of 10 micrometers, preload of 1Newton, and force track of 125%. The DMA analysis is performed at aconstant 25° C. temperature according to the following time/relativehumidity (RH) profile: (i) 0% RH for 300 minutes (representing the drystate for storage modulus determination), (ii) 50% RH for 600 minutes,(iii) 90% RH for 600 minutes (representing the wet state for storagemodulus determination), and (iv) 0% RH for 600 minutes.

The E′ value (in MPa) is determined from the DMA curve according tostandard DMA techniques at the end of each time segment with a constantRH value. Namely, the E′ value at 0% RH (i.e., the dry-state storagemodulus) is the value at the end of step (i), the E′ value at 50% RH isthe value at the end of step (ii), and the E′ value at 90% RH (i.e., thewet-state storage modulus) is the value at the end of step (iii) in thespecified time/relative humidity profile.

The outsole film can be characterized by its dry-state storage modulus,its wet-state storage modulus, or the reduction in storage modulusbetween the dry-state and wet-state outsole films, where wet-statestorage modulus is less than the dry-state storage modulus. Thisreduction in storage modulus can be listed as a difference between thedry-state storage modulus and the wet-state storage modulus, or as apercentage change relative to the dry-state storage modulus.

8. Glass Transition Temperature Test

This test measures the glass transition temperature (T_(g)) of theoutsole film for a sample, where the outsole film is provided in neatform, such as with the Neat Film Sampling Procedure or the Neat MaterialSampling Procedure, with a 10-milligram sample weight. The sample ismeasured in both a dry state and a wet state (i.e., after exposure to ahumid environment as described herein).

The glass transition temperature is determined with DMA using a DMAanalyzer commercially available under the tradename “Q2000 DMA ANALYZER”from TA Instruments, New Castle, Del., which is equipped with aluminumhermetic pans with pinhole lids, and the sample chamber is purged with50 milliliters/minute of nitrogen gas during analysis. Samples in thedry state are prepared by holding at 0% RH until constant weight (lessthan 0.01% weight change over 120 minute period). Samples in the wetstate are prepared by conditioning at a constant 25° C. according to thefollowing time/relative humidity (RH) profile: (i) 250 minutes at 0% RH,(ii) 250 minutes at 50% RH, and (iii) 1,440 minutes at 90% RH. Step(iii) of the conditioning program can be terminated early if sampleweight is measured during conditioning and is measured to besubstantially constant within 0.05% during an interval of 100 minutes.

After the sample is prepared in either the dry or wet state, it isanalyzed by DSC to provide a heat flow versus temperature curve. The DSCanalysis is performed with the following time/temperature profile: (i)equilibrate at −90° C. for 2 minutes, (ii) ramp at +10° C./minute to250° C., (iii) ramp at −50° C./minute to −90° C., and (iv) ramp at +10°C./minute to 250° C. The glass transition temperature value (in Celsius)is determined from the DSC curve according to standard DSC techniques.

9. Impact Energy Test

This test measures the ability of an outsole film sample to shed soilunder particular test conditions, where the sample is prepared using theCo-extruded Film Sampling Procedure or the Neat Film Sampling Procedure(to obtain a suitable sample surface area). Initially, the sample isfully immersed in a water bath maintained at 25° C. for 24 hours), andthen removed from the bath and blotted with a cloth to remove surfacewater.

The saturated test sample is then adhered to an aluminum block modeloutsole having a 25.4-millimeter thickness and a 76.2 millimeters×76.2millimeters surface area, using a room temperature-curing two-part epoxyadhesive commercially available under the tradename “LOCTITE 608” fromHenkel, Düsseldorf, Germany. The adhesive is used to maintain theplanarity of the soaked sample, which can curl when saturated.

Four polyurethane cleats, which are commercially available under thetrade name “MARKWORT M12-EP” 0.5-inch (12.7 millimeter) tall cleats fromMarkwort Sporting Goods Company, St. Louis, Mo., are then screwed intothe bottom of the block in a square pattern with a 1.56-inch(39.6-millimeter) pitch. As a control reference, four identical cleatsare attached to an aluminum block model outsole without an outsole filmsample attached.

To clog the model outsole cleats, a bed of soil of about 75 millimetersin height is placed on top of a flat plastic plate. The soil iscommercially available under the tradename “TIMBERLINE TOP SOIL”, model50051562, from Timberline (subsidiary of Old Castle, Inc., Atlanta, Ga.)and was sifted with a square mesh with a pore dimension of 1.5millimeter on each side. The model outsole is then compressed into thesoil under body weight and twisting motion until the cleats touch theplastic plate. The weight is removed from the model outsole, and themodel outsole is then twisted by 90 degrees in the plane of the plateand then lifted vertically. If no soil clogs the model outsole, nofurther testing is conducted.

However, if soil does clog the model outsole, the soil is knocked looseby dropping a 25.4-millimeter diameter steel ball weighing 67 grams ontothe top side of the model outsole (opposite of the test sample andclogged soil). The initial drop height is 152 millimeters (6 inches)above the model outsole. If the soil does not come loose, the ball dropheight is increased by an additional 152 millimeters (6 inches) anddropped again. This procedure of increasing the ball drop height by 152millimeter (6 inch) increments is repeated until the soil on the bottomof the outsole model is knocked loose.

This test is run 10 times per test sample. For each run, the ball dropheight can be converted into unclogging impact energy by multiplying theball drop height by the ball mass (67 grams) and the acceleration ofgravity (9.8 meters/second²). The unclogging impact energy in Joulesequals the ball drop height in inches multiplied by 0.0167. Theprocedure is performed on both the model outsole with the outsole filmsample and a control model outsole without the outsole film, and therelative ball drop height, and therefore relative impact energy, isdetermined as the ball drop height for the model outsole with theoutsole film sample divided by the control model outsole without theoutsole film. A result of zero for the relative ball drop height (orrelative impact energy) indicates that no soil clogged to the modeloutsole initially when the model outsole was compressed into the testsoil (i.e., in which case the ball drop and control model outsoleportions of the test are omitted).

10. Soil Shearing Footwear Test

This test measures the mud shearing ability of an article of footwear,and does not require any sampling procedure. Initially, the outsole ofthe footwear (while still attached to the upper) is fully immersed in awater bath maintained at 25° C. for 20 minutes), and then removed fromthe bath and blotted with a cloth to remove surface water, and itsinitial weight is measured.

The footwear with the soaked outsole is then placed on a last (i.e.,foot form) and fixed to a test apparatus commercially available underthe tradename “INSTRON 8511” from Instron Corporation, Norwood, Mass.The footwear is then lowered so that the cleats are fully submerged inthe soil, and then raised and lowered into the soil at an amplitude of10 millimeters for ten repetitions at 1 Hertz. With the cleats submergedin the soil, the cleat is rotated 20 degrees in each direction ten timesat 1 Hertz. The soil is commercially available under the tradename“TIMBERLINE TOP SOIL”, model 50051562, from Timberline (subsidiary ofOld Castle, Inc., Atlanta, Ga.), and the moisture content is adjusted sothat the shear strength value is between 3 and 4 kilograms/cm² on ashear vane tester available from Test Mark Industries (East Palestine,Ohio.

After the test is complete, the footwear is carefully removed from thelast and its post-test weight is measured. The difference between thepost-test weight and the initial weight of the footwear, due to soilaccumulation, is then determined.

EXAMPLES

The present disclosure is more particularly described in the followingexamples that are intended as illustrations only, since numerousmodifications and variations within the scope of the present disclosurewill be apparent to those skilled in the art. Unless otherwise noted,all parts, percentages, and ratios reported in the following examplesare on a weight basis, and all reagents used in the examples wereobtained, or are available, from the chemical suppliers described below,or may be synthesized by conventional techniques.

1. Footwear Outsole Water Uptake Analysis

Test samples for Examples 1-5 were measured for water uptake capacitiesover multiple soaking durations. Each test sample was taken from aglobal football/soccer shoe outsole having an outsole film of thepresent disclosure. Each outsole was initially manufactured byco-extruding the outsole film with a backing substrate having asubstrate thickness of 0.4 millimeters, where the backing substratematerial was an aromatic thermoplastic polyurethane commerciallyavailable under the tradename “ESTANE 2103-87AE” from LubrizolCorporation, Wickliffe, Ohio.

For Examples 1-3, the outsole film material was a thermoplasticpolyurethane hydrogel commercially available under the tradename“TECOPHILIC TG-500” from the Lubrizol Corporation, Wickliffe, Ohio,which included copolymer chains having aliphatic hard segments andhydrophilic soft segments (with polyether chains). For Examples 4 and 5,the outsole film material was a lower-water-uptake thermoplasticpolyurethane hydrogel commercially available under the tradename“TECOPHILIC HP-60D-60” from the Lubrizol Corporation, Wickliffe, Ohio.

For each example, the resulting co-extruded web was then sheeted, vacuumthermoformed, and trimmed to dimensions for an outsole face. The outsoleface was then back injected with another thermoplastic polyurethanecommercially available under the tradename “DESMOPAN DP 8795 A” fromBayer MaterialScience AG, Leverkusen, Germany to produce the outsolehaving the outsole film as the ground-facing surface, and the extrudedbacking substrate and back-injected material collectively forming theoutsole backing plate. Footwear uppers were then adhered to the topsides of the produced outsoles to provide the article of footwear.

Test samples for each example were then taken as described above in theFootwear Sampling Procedure, with the exception of the sample sizesdescribed below. In particular, annular test samples including theoutsole film and the outsole backing plate were cut out of the footwear.This was performed by initially cutting off the upper from the outsolenear the biteline where the outsole and upper meet.

A small guide hole in the center of the sample was then created(creating an inner diameter for the sample) to assist in cutting theannular sample with the desired outer diameter. All removable layersremaining on the top side of the outsole backing plate after cuttingwere peeled away from the test samples, including the sockliner,strobel, and insole board, while some residual adhesive remained on thesample. Each sample was taken from a central location in its respectiveregion (i.e., near a longitudinal midline) and generally in-between thecleats.

Test samples for Examples 1-3 were respectively taken from the forefootregion, the midfoot region, and the heel region of the outsole. Testsamples for Examples 4 and 5 were respectively taken from the forefootregion and the midfoot region. Each sample was taken from a centrallocation in its respective region (i.e., near a longitudinal midline)and generally in-between the cleats.

For comparison purposes, outsole samples were also taken from a globalfootball/soccer footwear having a thermoplastic polyurethanecommercially available under the tradename “DESMOPAN DP 8795 A” fromBayer MaterialScience AG, Leverkusen, Germany; where the outsoles didnot include an outsole film of the present disclosure. For ComparativeExample A, an annular test sample was taken from the forefoot region ofthe outsole using the same technique as discussed above for Examples1-5. For Comparative Example B, a rectangular test sample was taken fromthe midfoot region of the outsole. Each sample was taken from a centrallocation in its respective region (i.e., near a longitudinal midline)and generally in-between the cleats.

The film thickness, outsole thickness, surface area, and film volume ofeach test sample was then measured and calculated. The water uptakecapacity for each test sample was then measured for different soakingdurations, pursuant to the Water Uptake Capacity Test. After eachsoaking duration, the total sample weight was recorded, and the wateruptake weight for each soaking duration was calculated by subtractingout the dry sample weight from the given recorded total sample weight.

The film weight was also calculated for each soaking duration bysubtracting out the weight of the sample outsole substrate, as describedin the Water Uptake Capacity Test. The outsole substrate weight wasdetermined by calculating its volume (from the outsole thickness andsurface area) and using the known density of the outsole backing platematerial. The water uptake capacity was then calculated for each soakingduration, as also described in the Water Uptake Capacity Test. Tables1A-1G shown below list the total sample weights, the water uptakeweights, the film weights, and the water uptake capacities for the testsamples of Examples 1-5 and Comparative Examples A and B over differentsoaking durations.

TABLE 1A Total Uptaken Sample Water Water Soak Time Weight Weight FilmWeight Uptake Sample (minutes) (grams) (grams) (grams) Capacity Example1 0 1.54 0.00 0.64 0% Example 1 2 1.72 0.18 0.77 28% Example 1 5 1.750.21 0.84 33% Example 1 10 1.84 0.30 0.90 47% Example 1 30 2.01 0.471.10 74% Example 1 60 2.18 0.64 1.22 101%

TABLE 1B Total Uptaken Sample Water Water Soak Time Weight Weight FilmWeight Uptake Sample (minutes) (grams) (grams) (grams) Capacity Example2 0 1.50 0.00 0.51 0% Example 2 2 1.68 0.18 0.67 35% Example 2 5 1.750.25 0.73 49% Example 2 10 1.84 0.34 1.04 66% Example 2 30 2.15 0.651.33 127% Example 2 60 2.40 0.90 1.49 176%

TABLE 1C Total Uptaken Sample Water Water Soak Time Weight Weight FilmWeight Uptake Sample (minutes) (grams) (grams) (grams) Capacity Example3 0 1.21 0.00 0.46 0% Example 3 2 1.36 0.15 0.51 32% Example 3 5 1.440.23 0.72 50% Example 3 10 1.52 0.31 0.88 67% Example 3 30 1.63 0.420.79 91% Example 3 60 1.80 0.59 1.12 127% Example 3 180 2.15 0.94 1.58203% Example 3 300 2.30 1.09 1.72 235% Example 3 1260 2.57 1.36 1.93294%

TABLE 1D Total Uptaken Sample Water Water Soak Time Weight Weight FilmWeight Uptake Sample (minutes) (grams) (grams) (grams) Capacity Example4 0 1.06 0.00 0.18 0% Example 4 2 1.08 0.02 0.31 11% Example 4 5 1.110.05 0.35 28% Example 4 10 1.06 0.00 0.34 0% Example 4 30 1.11 0.05 0.2828% Example 4 60 1.12 0.06 0.41 33% Example 4 180 1.14 0.08 0.38 44%Example 4 300 1.10 0.04 0.38 22% Example 4 1260 1.10 0.04 0.36 22%

TABLE 1E Total Uptaken Sample Water Water Soak Time Weight Weight FilmWeight Uptake Sample (minutes) (grams) (grams) (grams) Capacity Example5 0 1.14 0.00 0.21 0% Example 5 2 1.17 0.03 0.21 61% Example 5 5 1.07−0.07 0.24 6% Example 5 10 1.19 0.05 0.26 72% Example 5 30 1.18 0.040.26 66% Example 5 60 1.19 0.05 0.27 72% Example 5 180 1.20 0.06 0.2977% Example 5 300 1.19 0.05 0.36 72% Example 5 1260 1.20 0.06 0.24 77%

TABLE 1F Total Uptaken Sample Water Soak Time Weight Weight Sample(minutes) (grams) (grams) Comparative Example A 0 1.26 0.00 ComparativeExample A 2 1.60 0.34 Comparative Example A 5 1.62 0.36 ComparativeExample A 10 1.56 0.30 Comparative Example A 30 1.62 0.36 ComparativeExample A 60 1.57 0.31

TABLE 1F Total Uptaken Sample Water Soak Time Weight Weight Sample(minutes) (grams) (grams) Comparative Example B 0 1.05 0.00 ComparativeExample B 2 1.05 0.00 Comparative Example B 5 1.05 0.00 ComparativeExample B 10 1.05 0.00 Comparative Example B 30 1.05 0.00 ComparativeExample B 60 1.05 0.00 Comparative Example B 180 1.06 0.01 ComparativeExample B 300 1.05 0.00 Comparative Example B 1260 1.06 0.01

As shown in Tables 1A-1C, there is significant change in the weight ofthe samples for Example 1-3, which was believed to be due to the highabsorbance of the outsole film material. The samples of Examples 4 and 5were based on a lower-absorbent material and used a thinner applicationwhen compared to Examples 1-3. Both of these differences lead to lessresolution in the measurement, although the uptake percent (˜50% averagefor the two samples) is measurable. This illustrates how the wateruptake of an outsole film is dependent on the water uptake properties ofthe film material as well as the film thickness.

In comparison, the samples of Comparative Examples A and B demonstratedthe lack of water uptake for non-functional materials. In particular,the sample of Example A only showed a change in weight at the first timepoint, but no subsequent change. This is due to surface phenomenon ofthe sample (e.g., capillary action) rather than water uptake into theoutsole. In particular, the backing layer for Comparative Example A wasrough (i.e., has micropores unrelated to the polymer chemistry) andfibers associated with shoe construction adhered to the backing layerthat were not fully removed during sample preparation. On the otherhand, the sample of Comparative Example B had a smooth outsole surfaceand all potential contaminants are removed.

In addition to the water uptake capacities, the test samples of Examples1-5 and Comparative Examples A and B were measured for thickness andvolumetric swelling, pursuant to the Swelling Capacity Test, over thesame soaking durations referred to above. Tables 2A-2G list the measuredsurface areas and film thicknesses, and the calculated film volumes forthe test samples, and Tables 3A-3E list the film thickness increase, thepercentage film thickness increase, the film volume increase, thepercentage film volume increase.

TABLE 2A Surface Sample Film Film Soak Time Area Thickness Thicknessvolume Sample (minutes) (mm²) (mm) (mm) (mm³) Example 1 0 380 3.66 1.44548 Example 1 2 379 3.75 1.75 664 Example 1 5 410 3.75 1.77 726 Example1 10 410 3.90 1.90 779 Example 1 30 451 4.18 2.11 951 Example 1 60 4814.34 2.18 1049

TABLE 2B Surface Sample Film Film Soak Time Area Thickness Thicknessvolume Sample (minutes) (mm²) (mm) (mm) (mm³) Example 2 0 421 3.50 1.05442 Example 2 2 415 3.70 1.40 582 Example 2 5 436 4.22 1.45 633 Example2 10 472 4.20 1.90 897 Example 2 30 561 4.15 2.05 1150 Example 2 60 6124.18 2.10 1285

TABLE 2C Surface Sample Film Film Soak Time Area Thickness Thicknessvolume Sample (minutes) (mm²) (mm) (mm) (mm³) Example 3 0 347 2.95 1.15399 Example 3 2 347 3.08 1.28 444 Example 3 5 369 3.46 1.68 620 Example3 10 399 3.58 1.89 755 Example 3 30 404 3.70 1.68 678 Example 3 60 4493.75 2.15 964 Example 3 180 513 4.00 2.65 1359 Example 3 300 530 4.182.80 1485 Example 3 1260 581 4.35 2.87 1667

TABLE 2D Surface Sample Film Film Soak Time Area Thickness Thicknessvolume Sample (minutes) (mm²) (mm) (mm) (mm³) Example 4 0 363 2.41 0.43156 Example 4 2 366 2.56 0.73 267 Example 4 5 372 2.57 0.80 298 Example4 10 371 2.47 0.78 290 Example 4 30 374 2.47 0.65 243 Example 4 60 3792.55 0.93 352 Example 4 180 373 2.55 0.87 324 Example 4 300 386 2.530.85 328 Example 4 1260 379 2.40 0.81 307

TABLE 2E Soak Surface Sample Film Film Time Area Thickness Thicknessvolume Sample (minutes) (mm²) (mm) (mm) (mm³) Example 5 0 378 2.42 0.47178 Example 5 2 377 2.50 0.48 181 Example 5 5 386 2.50 0.54 208 Example5 10 385 2.52 0.58 223 Example 5 30 384 2.53 0.59 227 Example 5 60 3882.50 0.59 229 Example 5 180 389 2.57 0.65 253 Example 5 300 394 2.570.78 307 Example 5 1260 388 2.55 0.54 209

TABLE 2F Soak Surface Sample Time Area Thickness Sample (minutes) (mm²)(mm) Comparative Example A 0 405 2.90 Comparative Example A 2 417 2.90Comparative Example A 5 425 3.15 Comparative Example A 10 407 2.77Comparative Example A 30 416 2.77 Comparative Example A 60 426 2.87

TABLE 2G Soak Surface Sample Time Area Thickness Sample (minutes) (mm²)(mm) Comparative Example B 0 501 1.77 Comparative Example B 2 500 1.77Comparative Example B 5 502 1.77 Comparative Example B 10 503 1.75Comparative Example B 30 503 1.75 Comparative Example B 60 496 1.73Comparative Example B 180 499 1.73 Comparative Example B 300 503 1.74Comparative Example B 1260 501 1.73

TABLE 3A Film Percent Film Percent Soak Thickness Film Volume Film TimeIncrease Thickness Increase Volume Sample (minutes) (mm) Increase (mm)Increase Example 1 0 0  0% 0  0% Example 1 2 0.31 22% 116 21% Example 15 0.33 23% 178 33% Example 1 10 0.46 32% 231 42% Example 1 30 0.67 47%403 74% Example 1 60 0.74 51% 501 92%

TABLE 3B Film Percent Film Percent Soak Thickness Film Volume Film TimeIncrease Thickness Increase Volume Sample (minutes) (mm) Increase (mm)Increase Example 2 0 0  0% 0  0% Example 2 2 0.35 33% 140  32% Example 25 0.40 38% 191  43% Example 2 10 0.85 81% 455 103% Example 2 30 1.00 95%708 160% Example 2 60 1.05 100%  843 191%

TABLE 3C Film Percent Film Percent Soak Thickness Film Volume Film TimeIncrease Thickness Increase Volume Sample (minutes) (mm) Increase (mm)Increase Example 3 0 0  0% 0  0% Example 3 2 0.13 11% 45 11% Example 3 50.53 46% 221 55% Example 3 10 0.74 64% 356 89% Example 3 30 0.53 46% 27970% Example 3 60 1.00 87% 565 142%  Example 3 180 1.50 130%  960 240% Example 3 300 1.65 143%  1086 272%  Example 3 1260 1.72 150%  1268 318% 

TABLE 3D Film Percent Film Percent Soak Thickness Film Volume Film TimeIncrease Thickness Increase Volume Sample (minutes) (mm) Increase (mm)Increase Example 4 0 0  0% 0  0% Example 4 2 0.30 70% 111 71% Example 45 0.37 86% 142 91% Example 4 10 0.35 81% 134 85% Example 4 30 0.22 51%87 56% Example 4 60 0.50 116%  196 125%  Example 4 180 0.44 102%  168107%  Example 4 300 0.42 98% 172 110%  Example 4 1260 0.38 88% 151 96%

TABLE 3E Film Percent Film Percent Soak Thickness Film Volume Film TimeIncrease Thickness Increase Volume Sample (minutes) (mm) Increase (mm)Increase Example 5 0 0  0% 0  0% Example 5 2 0.01  2% 3  2% Example 5 50.07 15% 30 17% Example 5 10 0.11 23% 45 26% Example 5 30 0.12 26% 4928% Example 5 60 0.12 26% 51 29% Example 5 180 0.18 38% 75 42% Example 5300 0.31 66% 129 73% Example 5 1260 0.07 15% 31 18%

As can be seen in Tables 2A-2G and 3A-3E, the samples of Examples 1-5all show significant changes in both thickness and volume upon waterabsorption. The thickness and volume change is even resolved forExamples 3 and 4, where the water uptake test showed less change. Thesamples for Comparative Examples A and B, however, did not show anychange in thickness or volume. Even when Comparative Example A showed achange in weight, as discussed above, there was no correspondingthickness change because the physisorbed water was not acting to swellthe samples, as is the case for Examples 1-5.

2. Outsole Film Water Uptake Capacity

Various samples of outsole films for Examples 6-18 were also tested forwater uptake capacities at 1 hour and 24 hours, pursuant to the WaterUptake Capacity Test with either the Co-Extruded Film Sampling Procedure(co-extruded form) or the Neat Film Sampling Procedure (neat form). Forthe co-extruded forms, the backing substrate was a thermoplasticpolyurethane commercially available under the tradename “DESMOPAN DP8795 A” from Bayer MaterialScience AG, Leverkusen, Germany.

The outsole film material for Examples 6-8 was a thermoplasticpolyurethane hydrogel commercially available under the tradename“TECOPHILIC TG-500” from the Lubrizol Corporation, Wickliffe, Ohio (samematerial as for Examples 1-3). For Example 6, the film was in neat formwith a 0.25-millimeter film thickness. For Example 7, the film was in aco-extruded form with a 0.13-millimeter film thickness. For Example 8,the film was also in a co-extruded form, but with a 0.25-millimeter filmthickness.

The outsole film material for Examples 9 and 10 was a lower-water-uptakethermoplastic polyurethane hydrogel commercially available under thetradename “TECOPHILIC HP-60D-60” from the Lubrizol Corporation,Wickliffe, Ohio (same as for Examples 4 and 5). For Example 9, the filmwas in a co-extruded form with a 0.25-millimeter film thickness. ForExample 10, the film was in a neat form with a 0.13-millimeter filmthickness.

The outsole film material for Example 11 was a thermoplasticpolyurethane hydrogel commercially available under the tradename“TECOPHILIC TG-2000” from the Lubrizol Corporation, Wickliffe, Ohio,where the film was in a neat form with a 0.13-millimeter film thickness.The outsole film material for Example 12 was a thermoplasticpolyurethane hydrogel commercially available under the tradename“TECOPHILIC HP-93A-100” from the Lubrizol Corporation, Wickliffe, Ohio,where the film was in a co-extruded form with a 0.13-millimeter filmthickness.

The outsole film materials for Examples 13-17 were also thermoplasticpolyurethane hydrogels derived from chain-extended TDI isocyanates andpolyether glycols, where the polyether glycol concentrations were variedto adjust the water uptake capacities. For these examples, the filmswere pressed into thick neat films having 3-millimeter film thicknesses.

In comparison to Examples 1-17, the outsole film material for Example 18was a thermoplastic polyamide-polyether block copolymer hydrogelcommercially available under the tradename “PEBAX MH1657” from Arkema,Inc., Clear Lake, Tex., where the film was in a neat form with a0.13-millimeter film thickness. Table 4 lists the water uptakecapacities for the samples of Examples 6-18.

TABLE 4 Water Water Uptake Capacity Uptake Capacity Sample (1 hour) (24hours) Example 6 341%  468% Example 7 260%  — Example 8 153%  168%Example 9 —  44% Example 10 29%  80% Example 11 415%  900% Example 1244% — Example 13 55% 238% Example 14 60% 250% Example 15 35% 184%Example 16 40% 167% Example 17 15%  69% Example 18 116%  100%

As shown, Examples 6-8 in Table 4 demonstrate the effects ofconstraining the outsole film to a co-extruded backing substrate.Examples 9 and 10 demonstrate the same effects with a lower uptakematerial. Example 11 is a neat film with relatively high water uptake,while Example 12 is a coextruded form of a neat resin that has a wateruptake capacity in-between those of Examples 6 and 10. Examples 13-17also exhibited good water uptakes, and included considerably thickerfilms (by about a factor of 10).

3. Outsole Film Water Uptake Rate and Swelling

Several samples (for Examples 1, 4, 6-8, and 10-12) were also tested forwater uptake rates and swell capacities, pursuant to the Water UptakeRate Test and the Swell Capacity Test. Table 5 lists the test resultsfor the samples of Examples 1, 4, 6-8, and 10-12.

TABLE 5 Water Percent Percent Uptake Rate Film Thickness Film Volume(grams/m²- Increase Increase Sample minutes^(1/2)) (1 hour) (1 hour)Example 1 235 73% 130%  Example 4 58 72% 75% Example 6 752 89% 117% Example 7 173 318%  64% Example 8 567 177%  77% Example 10 33 43% 88%Example 11 1270 69% 92% Example 12 172 153%  70%

As shown, the tested samples exhibited varying water uptake rates, wherethe samples having higher water uptake capacities (from Table 4) andthat were in neat form exhibited faster water uptake rates. Moreover,the swelling thickness and volume increases shown in Table 5 generallycorresponded to the water uptake capacities shown above in Table 4.

4. Outsole Film Contact Angle

The samples for Examples 6, 7, 10-12, and 18 were also tested for dryand wet contact angles, pursuant to the Contact Angle Test. Table 6below lists the corresponding dry and wet contact angles with theirvariations, as well as the difference in contact angle between the dryand wet measurements.

TABLE 6 Average Average Dry Film Dry Film Wet Film Wet Film ContactContact Contact Contact Contact Angle Angle Angle Angle Angle Sample(degrees) (std dev) (degrees) (std dev) Difference Example 6 87.6 2.666.9 4.9 20.7 Example 7 86.6 1.1 57.4 5.5 29.2 Example 10 95.6 3.2 72.52.5 23.1 Example 11 79.5 2.4 64.7 2.3 14.8 Example 12 97.1 2.5 95.5 4.71.7 Example 18 66.2 5.0 52.0 3.7 14.2

The samples of Examples 6 and 7 show that there is no difference incontact angles between a neat film and the co-extruded film at therelevant thicknesses because contact angle is a surface property. Thesamples of Examples 10 and 11 show that a higher contact angle isgenerally present on a lower water uptake material (Example 10) comparedto a high water uptake material (Example 11) The sample of Example 18,based on polyamide copolymer chemistry, demonstrates that the basechemistry can affect the dry contact angle. However, in all cases, asubstantial reduction in contact angle is seen for wet films whencompared to dry samples. As can be appreciated from the discussionherein, a decrease in contact angle can demonstrate a change in adhesiveproperties between the soil and outsole.

5. Outsole Film Coefficient of Friction

The samples for Examples 7, 10-12, and 18-21 were also tested for dryand wet coefficients of friction, pursuant to the Coefficient OfFriction Test. The outsole film material for Example 19 was the samethermoplastic polyamide hydrogel as used for Example 18, where the filmwas in a co-extruded form with a 0.13-millimeter film thickness.

The outsole film material for Examples 20 and 21 was a thermoplasticpolyamide-polyether block copolymer hydrogel commercially availableunder the tradename “PEBAX MV1074” from Arkema, Inc., Clear Lake, Tex.For Example 20, the film was in a neat form with a 0.13-millimeter filmthickness. For Example 21, the film was in a co-extruded form with a0.13-millimeter film thickness.

For comparison purposes, a film of a thermoplastic polyurethane(commercially available under the tradename “DESMOPAN DP 8795 A” fromBayer MaterialScience AG, Leverkusen, Germany; Comparative Example C),and a non-hydrogel thermoplastic polyamide (commercially available fromArkema, Inc., Clear Lake, Tex.; Comparative Example D) were also tested.Table 7 below lists the corresponding dry and wet coefficients offriction, as well as the percent reductions in the coefficients offriction between the dry and wet measurements.

TABLE 7 Coefficient Coefficient Percent Reduction of Friction ofFriction in Coefficient Sample (dry) (wet) of Friction Example 7 0.30.13 57% Example 10 0.63 0.11 83% Example 11 0.29 0.06 79% Example 121.22 0.54 56% Example 18 0.6 0.76 −27%  Example 19 0.65 0.31 52% Example20 0.59 0.47 20% Example 21 0.53 0.26 51% Comparative 0.59 0.71 −20% Example C Comparative 0.37 0.35  5% Example D

A comparison the results between Examples 7, 10-12, and 19-21 toComparative Examples C and D in Table 7 illustrate how the water take upby the outsole films of the present disclosure can reduce thecoefficient of friction of the film surfaces. Example 18 exhibited anincrease in coefficient of friction after soaking. This is believed tobe due to a partial saturation state for the film, where the waterpresent at or near the film surface is being drawn into the film,creating a transitory tackier surface. As the film for Example 18reached saturation point, its coefficient of friction also reduced belowits dry-state value.

6. Outsole Film Storage Modulus

The samples for Examples 6, 8-12, and 18 were also tested for reductionsin storage modulus values, pursuant to the Storage Modulus Test. Table 8lists the storage modulus values at 0% relative humidity (RH), 50% RH,and 90%, as well as the percent reductions between the 0% and 50% RH,and between the 0% and 90% RH.

TABLE 8 E′ E′ E′ (MPa) (MPa) (MPa) ⊐E′50 ⊐E′90 Sample 0% RH 50% RH 90%RH (%) (%) Example 6 766.6 548.3 0.03 29% 100%  Example 8 151.7 119 41.922% 72% Example 9 60.16 52.68 45.93 12% 24% Example 10 43.44 34.05 29.5822% 32% Example 11 514.9 396.8 0.86 23% 100%  Example 12 44.7 38.2 34.515% 23% Example 18 119.7 105.3 64.6 12% 46%

The mechanical properties of the sample films and their changes uponwater uptake can demonstrate both functional and durability properties.First, storage modulus is inversely related to compliance, and acompliant surface is useful in preventing or reducing the adhesion ofsoil to the outsole, as discussed above. A decrease in the modulus uponexposure to moisture is representative of an increase in compliance andmore functional material. Additionally, the outsole films of the presentdisclosure as saturated desirably have suitable upper values for thestorage modulus in order to maintain structural integrity for longerdurations.

7. Outsole Film Glass Transition Temperature

The samples for Examples 6, 8-12, and 18 were also tested for reductionsin glass transition temperatures, pursuant to the Glass TransitionTemperature Test. Table 9 lists the dry and wet glass transitiontemperatures, as well as their reductions between the dry and wetstates.

TABLE 9 T_(g, dry) T_(g, wet) ΔT_(γ) Sample (° C.) (° C.) (° C.) Example6 −27.5 −70 −42.5 Example 8 −30 −63 −33 Example 9 −25 −31 −6 Example 10−20 −37.1 −17.1 Example 11 — −63 — Example 12 −49.59 −60.59 −11 Example18 −54.93 −64.76 −9.83

As can be seen in Table 9, water can act to plasticize the outsole filmif it is taken up at the molecular level, and can act to differentiatethis mechanism from materials that absorb water through capillary forceor physisorption. A larger drop in the glass transition temperature willtypically be seen for a neat film (Examples 6 and 10) compared to aco-extruded version (Examples 8 and 9, respectively.) Interestingly,Example 11 showed no measurable glass transition when dry, whichsuggests that there is not enough amorphous material in the sample tocreate a measurable signal. The appearance of a glass transitiontemperature after water uptake suggests that the material is eithersignificantly plasticized and/or the absorbent regions are highlycrystalline in the absence of water.

8. Impact Energy Test

The samples for Examples 7, 12, 14, 16, 17, 19, and 21 were also testedfor their abilities in shedding soil, pursuant to the Impact EnergyTest, as shown below in Table 10.

TABLE 10 Sample Relative Impact Energy Example 7 0.60 Example 12 0.90Example 14 0.00 Example 16 0.00 Example 17 0.83 Example 19 1.03 Example21 0.95

All of the samples listed in Table 10, with the exception of Example 19,show a reduction in the adhesion energy between the film and soil whencompared to the unmodified aluminum block. Example 19 showed a slightincrease in adhesion energy. However, this is believed to be due to thethickness of the sample (3 millimeters), which prevented the film fromreaching its saturation point during the soaking step. In comparison,the other samples listed in Table 10 illustrated improvements inreducing soil adhesion.

9. Soil Shearing of Footwear

Global football/soccer footwear for Examples 22 and 23 were also testedfor soil shearing abilities, pursuant to the Soil Shearing FootwearTest, where Example 22 included the same footwear and outsole films asdiscussed above for Examples 1-3, and where Example 23 included the samefootwear and outsole films as discussed above for Examples 4 and 5.

After the test, the sample for Example 22 had a weight gain of 28.3grams, and the sample for Example 23 had a weight gain 37.4 grams. Bothexamples demonstrated that the use of the soaked outsole films in atypical field of use achieve the desired results of reducing soilaccumulation. Furthermore, the film with a higher degree of water uptakecapacity, water uptake rate, and swelling capacity (Example 22) showedmore improvement in reducing soil accumulation compared to the lowerwater uptake film (Example 23).

10. Field Use

Global football/soccer footwear for Examples 24 and 25 were also testedon a closed course during game play, where Example 24 included the samefootwear and outsole films as discussed above for Examples 1-3 and 22,and where Example 25 included the same footwear and outsole films asdiscussed above for Examples 4, 5, and 23. Five pairs of the footwearfor Example 24 were tested, one pair of the footwear for Example 25 wastested, and two pairs of control footwear were tested (which did notinclude an outsole film) (Comparative Examples E and F). The footwear,initially clear of all debris, were then worn by players on the closedcourse while playing soccer for 90 minutes during a rainy day.

The first 45 minutes were played on a natural grass field, and second 45minutes were played on an organic/sand/clay mix field. After the90-minute playing session, the shoes were investigated for theaccumulation of debris over the course of the game. As seen from theimages in FIGS. 20B-20F, the five pairs of shoes with the outsole filmof Example 24 accumulated little to no debris, while the two pairs ofcontrol footwear for Comparative Examples E and F accumulated asubstantial amount of debris. The pair of shoes with the outsole film ofExample 25 also accumulated debris (as shown in FIG. 20A), but theaccumulated amount was somewhat less than the control footwear ofComparative Examples E and F (as shown in FIGS. 20G and 20H). Thisillustrates the difference in preventing soil accumulation based on thewater uptake capacities of the outsole films of the present disclosure.

Additionally, the footwear for Examples 24 and 25 were also used forextended durations during games on the closed course to demonstrate thelimits of their durabilities. The outsole films for the footwear of bothExamples 24 and 25 continue to perform the same after 100 hours of gameplay without any significant abrasion or delamination. As such, theoutsole films of the present disclosure are suitable for use asground-facing surfaces for footwear outsoles.

Although the present disclosure has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the disclosure.

What is claimed:
 1. An outsole for an article of footwear, the outsolecomprising: an outsole backing member, wherein one or more tractionelements are operably secured to the outsole backing member; and a filmsecured to the outsole backing member and defining an external surfaceof the outsole, wherein the film comprises a hydrogel, wherein theoutsole backing member compositionally comprises a thermoplasticpolyurethane, and wherein the hydrogel comprises a crosslinked polymericnetwork having copolymer chains that are physically crosslinked.
 2. Theoutsole of claim 1, wherein the copolymer chains are substantially freeof aromatic groups.
 3. The outsole of claim 1, wherein the film has adry-state film thickness ranging from 0.1 millimeters to 1 millimeter.4. The outsole of claim 1, wherein the film has a saturated-state filmthickness ranging from 0.25 millimeters to 2 millimeters.
 5. The outsoleof claim 1, wherein at least one of the one or more traction elements isselected from the group consisting of: a cleat, a stud, a spike, and alug.
 6. The outsole of claim 1, wherein the one or more tractionelements are integrally formed with the outsole.
 7. The outsole of claim1, wherein the one or more traction elements are removable tractionelements.
 8. The outsole of claim 1, wherein each of the one or moretraction elements comprises a terminal edge, and wherein the film doesnot cover the terminal edges of any of the one or more tractionelements.
 9. The outsole of claim 1, wherein the crosslinked polymericnetwork has one or more carbamate linkages.
 10. The outsole of claim 1,wherein the hydrogel comprises crystalline regions and amorphoushydrophilic regions, wherein the amorphous hydrophilic regions arecovalently bonded to the crystalline regions.
 11. The outsole of claim1, wherein the amorphous hydrophilic regions are bonded to thecrystalline regions with carbamate linkages.
 12. The outsole of claim 1,wherein the amorphous hydrophilic regions are present in the hydrogel ata ratio of at least 20:1 by weight relative to the crystalline regions.13. The outsole of claim 1, wherein the outsole is operably secured to afootwear upper.
 14. An article of footwear, comprising: an outsolehaving an outsole backing member, wherein one or more traction elementsare operably secured to the outsole backing member; and a film securedto the outsole backing member and defining an external surface of theoutsole, wherein the film comprises a hydrogel, wherein the outsolebacking member compositionally comprises a thermoplastic polyurethane,and wherein the hydrogel comprises a crosslinked polymeric networkhaving copolymer chains that are physically crosslinked; and an upper,wherein the upper is operably secured to the outsole.
 15. The article ofclaim 14, wherein the film has a dry-state film thickness ranging from0.1 millimeters to 1 millimeter and wherein the film has asaturated-state film thickness ranging from 0.25 millimeters to 2millimeters.
 16. The article of claim 14, wherein the hydrogel comprisescrystalline regions and amorphous hydrophilic regions, wherein theamorphous hydrophilic regions are covalently bonded to the crystallineregions, wherein the amorphous hydrophilic regions are present in thehydrogel at a ratio of at least 20:1 by weight relative to thecrystalline regions.
 17. The article of claim 16, wherein thecrosslinked polymeric network has one or more carbamate linkages,wherein the amorphous hydrophilic regions are bonded to the crystallineregions with carbamate linkages.
 18. The article of claim 14, whereinthe one or more traction elements are integrally formed with theoutsole, wherein at least one of the one or more traction elements isselected from the group consisting of: a cleat, a stud, a spike, and alug.
 19. The article of claim 14, wherein the one or more tractionelements are removable traction elements, wherein at least one of theone or more traction elements is selected from the group consisting of:a cleat, a stud, a spike, and a lug.
 20. The article of claim 14,wherein each of the one or more traction elements comprises a terminaledge, and wherein the film does not cover the terminal edges of any ofthe one or more traction elements.